Favorite Game Mechanic(s)—And Why?

To get to know each other, and other games we might not otherwise play, I'd like to start a positive thread about what we love about our games.

In this thread, I'd ask for you to tell us what game mechanics you love, and why. I'll start off.

I love the 4dF roll in Fate because it's a comfortable handful of dice, and the option of getting a lower result than my skill is something I've not seen in any other game.

I love that players roll all the dice in Apocalypse World-powered games. As a GM, it takes enough off of me that I can spend more time on the story and being a dick to the characters (not the players!). Less rolling is almost always good, in my opinion.

What about you? What mechanics do you like, and why?

I like Fate's simplicity and will be trying it soon. Otherwise, I've only played D&D 5e, and rolling lower than your passive skill is always possible. I'm not sure about favourite mechanics yet but advantage/disadvantage is a smart idea

From the little I've played of the system I've found that I really like the Escalation Die in 13th Age. Neat way to move the combat along.

I have a few.

I love O.R.E.'s concept of height and width of a roll.

I love Earthdawn's Healing Surge (the original WotC probably copied for their 4th edition of D&D).

I love Earthdawn's and Undiscovered rule that you have to bind yourself to a major magic item in order to make it work. Both do them in a different manner, but it is an interesting concept nonetheless.

I love Dungeonslayer's innovative simplicity.

I love the concept of Steps in Earthdawn, which could, with a little bit of work, make for a wonderful Final Fantasy RPG.

I love Trailblazer's concept of Combat Reactions which greatly simplifies Attack of Opportunities and Aid Another in D20 3.X.

I love how GURPS somehow manages to simulate realism without being bogged down in a bunch of complex rules... well at least until you try making a vehicle, that is...

I love 1PG's simplicity, which despite having all the rules you need to play on one page, still manages to have some depth to its rules.

I love Fantasy Flight's Horizon series which really expends what D20 can do and takes it to new places (still would very much love to make a game of Spellslingers one of these days...).

I'm, going to agree with @kalael on O.R.E.'s system. It's a really interesting concept that I'm really interested to try. I picked up Monsters and Other Childish Things last year at Gen Con, but I have yet to actually try it out.

My favorite mechanic, however, is the use of Style Points in the Ubiquity engine. If you haven't heard of the Ubiquity engine, it's the system that is used in Hollow Earth Expedition. If you still don't know what I'm talking about, I heartily encourage you to check it out, it's a great system (link).

Players are awarded Style Points for good roleplaying, for helping the game move along, and for making the game fun for everyone. They can be used to increase the result of just about any roll, including many rolls for your fellow players, for mitigating damage, and for generally making your PCs awesome. They're similar to Bennys in Savage Worlds, but not quite as powerful. Every time I've played a game with tis system the players were always really engaged and they were excited about getting Style Points, spending Style Points, and using Style Points to help their fellow players so that everybody was awesome.

There is also a game coming out very soon called Clockwork: Dominion by Reliquary Game Studios. This game contains a really great system for resolving social conflict and convincing other characters to come around to your point of view. I don't think I've ever seen a social combat system done so well.

I love the Relationship Map in the Smallville RPG. It's a wonderful way to create a world together at the gaming table. It also creates ties between NPCs and PCs and gets everyone at the table invested in relationships. It's wonderful.

I enjoy skill challenges for chase scenes. I let my players describe the action. Roll if they fail I tell them how bad and sometimes the chase ends in a fight with very few issues and keeps everyone involved.

My favorite game mechanic is probably from Lasers & Feelings. You have two stats effectively combined into one number. If you’re using lasers (science, reason), you want to roll under your number. If you’re using feelings, (rapport, passion) you want to roll over your number. If you roll your number exactly, you have laser feelings. You get a special insight into what’s going on. Ask the GM a question and they’ll answer you honestly.

I love the Principle of Narrative Truth from Wushu, but it's not really a mechanic as much as a rule.

It may be minor, but I love the card-based initiative in Savage Worlds. It leaves no doubt as to who goes next in a combat, and the round-by-round determination keeps it interesting, not to mention the joy of getting that Joker card!

Also from Savage Worlds, but not exclusive to it, is the Exploding Dice or Acing for trait tests. It provides even an untrained character a chance at succeeding at a task.

I'm a big fan of the Jenga tower mechanic in DREAD. I borrowed it for a different game I was running where the character was attempting to defuse a bomb. To make the attempt, the player had to pull ten blocks from the tower in one minute. If he knocked over the tower, the bomb exploded. Pretty sure he was actually sweating when he pulled the tenth block with three seconds left

Jumping in quite late here, so echoing much of what has already been said.

I also like the card-based initiative of Savage Worlds - it creates the best tension.

Generally I like mechanics that give players some chance to hit back at blind (bad) luck, so bennies in SW, Fate points, effort in Numenera / The Strange, and inspiration in D&D 5e, though with the latter I prefer the modification I have heard on several podcasts of allowing any number of inspiration points to build up, not just one.

In related news, I like mechanics which make the "I'm the GM this is going to happen" thing palatable by mitigating it with Fate points, experience (GM interventions in Numenera) etc, and am for introducing this into systems where it isn't built in - so giving bennies or inspiration in these circumstances in SW and D&D 5e.

Again it's been mentioned, but systems where only the players roll are also really neat.

I love the use of cards in TORG: a drama deck which both the GM and players use the influence conditions in each scene, and also to affect events in game.

I love the specialized dice in FFG's Star Wars games: taking what are essentially FUDGE dice and making them so that you can actually have improved chances of success with character improvement.

I am a particular student of game systems' character improvement mechanisms. As such, I'm very fond of Third Edition Skyrealms of Jorune's character advancement: you mark what skills you've used in a session, and can spend XP on a chance to improve in that skill at the end of the session - none of this improving skills that you don't use. A common variant rule also allows the player to choose during character creation whether your character learns by success or by failure, and you get to mark the uses that succeeded or failed as appropriate. That has a great meta-game conundrum: do you choose failure, and thus improve skills faster in the early career of your character, or do you choose success, ensuring that you will be able to continue improving skills in your character's prime?

The character advancement system in Warhammer Fantasy RPG (1st edition) has always fascinated and delighted me. Characters have characteristics (what most would call attributes or stats), careers, and skills within those careers. You earn XP through adventuring and role-playing, then can spend those XP to improve any of those things...or to change careers. The mechanics of changing careers is wonderfully crunchy - sort of of a mini-game in itself.

Of course, I also love the Advantage/Disadvantage concept originally created in Champions. It influenced a bazillion other games, and rightly so: the idea of buying a character with points is awesome, and naturally leads to the idea that you can take negative traits in order to gain more points.

Finally, the idea of relationships between characters being determined by where players sit in Fiasco really tickles me, also that those adjacent players collaborate on creating their characters. In general, for an in-person game, Fiasco is magic.