What's the hardest skill to master in airsoft?

Not getting mad after spending nearly the entire game sneaking up behind the enemy team, and then getting shot by a teammate.

Knowing when to hold your spot, when to move and when to stop charging straight into the same doorway for the fifth time 😂

That sometimes its best to not take a shot and give away your position because you know that you'll be able to invade a base once a few people disappear