I've mentioned before the 5e game I'm in that started in January that is still on basically the first encounter. The DM seems to be new to running PbP campaigns and waits for days between his posts. He said he wants to run it as a sandbox, but not only has he not given us much information about the city we're in, he kind of cornered my character and another when he had the town guard - armed with swords AND guns - surround us on suspicion of using magic. I did some pretty good RP but failed the persuasion rolls (because hello, it's ME), so we agreed to come quietly and be taken to see the magistrate.
That was SIX WEEKS AGO. We actually stood there, waiting for him to have his ridiculously overarmed town guard regiment escort us to the magistrate, while his very occasional posts never advanced the plot. A couple of other PCs tried persuasion rolls on our behalf and failed (probably because they were about me - it's ALWAYS about me, after all), but instead of the DM saying, right, that's it, off we go... he just kept having the captain of the guard give retorts as we crawled slowly to the dock. Meanwhile, he posts every few days saying, "I'm just giving everyone a chance to post before I move on," when EVERYONE HAS ALREADY POSTED AT LEAST ONCE. And we're all out of ideas for RP at this point. How many times are my character and the other guy's required to say, "Yep, still comin' quietly, boss!" like the chain gang of Cool Hand Luke?