Something I've been working through as a coach and a player, is the problem of balancing stage time. You want to feel responsibility for the show, but you also don't want it to feel like a one-man-team. Should you play aggressively or politely? There's certainly some individual wisdom required, but I think I've decided what the default mode should be. Here's a game theory chart to explain:
No matter what Player 1 does, Player 2 should always play aggressively. No matter what Player 2 does, Player 1 should always play aggressively. Best of all, if both follow this strategy it results in the best possible scene, fast-paced and exciting. And you though Game Theory was just for classrooms and reality TV.
This has also been posted at The College Improv Resource.