a common tendency is to try something, and fail/get shot down, and then spend a good chunk of time hating yourself and thinking about how you could have done it better. what you should be doing is rolling with it and trying again.

so: put a chess app on your phone, or bring a sudoku book with you, or whatever. when you catch yourself beating yourself up, do puzzles for 30 seconds to break the death spiral, and then get back to it.

bonus points if you pick something that doesn't make you look like a complete tool if someone sees you doing it at a bar. but even if it is dorky, 30 seconds of looking like a dork is better than 3 hours of self loathing.