There was a great scene in the Krav Maga episode of Fight Quest where Jimmy gets floored by a Thai kick to the leg. He curses and growls as he tries to gather himself and get back on his feet, but the instructor says something to the effect of, "Nobody cares about your screaming. You need to get up and keep fighting."
Which is, in effect what the episode was about. And really, what much of your training is all about - keeping your cool when things aren't going your way.
Getting angry doesn't accomplish much. Unless you've got the ability to "Hulk out" (recall Chris Leben vs. Terry Martin), you're really only doing yourself a disservice. A couple months ago, Sifu Z delivered a great post-class pep talk. He said, "when you get frustrated, you're not mad at the other person or the situation, you're mad at yourself. You're frustrated because you're not as good as you thought you were."
"But he hit me in the nose."
- Stress testing like Jimmy's mini-kumite, or me getting handled by a guy not even trying is an awesome opportunity to figure out how comfortable you are with how much you suck - except for the time you actually spend in the "middle" as it were - then it's the most embarrassing and frustrating few minutes of your life
- If you make it to the end, you've "won." If you can swallow your ego and quit in the middle, you've "won." Hell, you can still win if you spend your time complaining and later realize that you made a fool of yourself and work to correct it
- Quit yer bellyachin'
CC-licensed image from _KoAn_