I've been absent from Story Games (and actual story gaming) for a long time but I've been thinking about getting back into it and running another game, and I've noticed a rather ugly pattern in my previous GM'ing efforts that I don't quite understand but has held fast over several different systems. Namely, I have trouble keeping a game going past a few sessions. I do fine with one-shots or with the first session of games, everybody seems to enjoy it and look forward to more, but the second session gets... wobbly. Even if I have it planned out well, it doesn't seem to run as smoothly and I start to feel insecure about my GM'ing, and by the third session I get extremely anxious and freeze up and that usually kills the game.
I've tried to get around this by only running adapted modules so I have someone else's work to lean on, and by running kind of a picaresque game where each episode takes place without much consideration for continuity -- time passes and the characters continue their work and we pick up when something cool happens a year later -- but it still doesn't help, and I feel bad these days offering to run anything more than a one-shot because I'm not sure I can deliver on it. I'm curious if anybody else has had similar experiences.