I never knew tanks could do it, since when they punch things they send them flying... Wait, actually, it would be impossible, since the tank wouldn't spawn until they got to the top of the elevator. They used to have something where you could be a boomer and punch a generator or forklift in the way of the elevator, but they got rid of that.
Anyway, for me, the most annoying thing in a videogame is a long combo of hits that you can't get out of. I know it only happens in fighting games usually, but it gets really annoying when you fail to block once, they start hitting you, and you keep trying to escape it while they take a good chunk of health.
Grinding is a close second, and I would have to say, invisible walls are annoying, but only in certain circumstances/games.