Over at his blog "Hardcore Zen", Zen teacher (and punk rock bassist) Brad Warner has a very good piece on the Buddhist concept of "desire" as the origin of suffering:
This is why meditation is such a brilliant solution. It forces us to confront our desires head-on, over and over and over again. When you sit in non-goal-seeking meditation you are forced into direct confrontation with some very basic desires such as the desire to not be sitting there facing a blank wall, the desire to be doing something productive or at least interesting, the desire to not be bored…
You sit there and you meet your desires moment by moment and you do not do anything at all to satisfy even the easiest ones to satisfy. You want to move, but you don’t. You want this meditation session to be a good one full of peaceful feelings and bliss, but you stick with it even when it’s full of conflict and distractions. You just sit still.
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What we’re working on when we do zazen is the exact opposite of “following our bliss.” We are following our lack of bliss, following our lack of satisfaction.
This should also sound familiar to martial arts practitioners, and illustrates why ultimately Karate and Zen are one. You have a desire to not do this same kata for the umpteenth time in a row. You have a desire to not be doing push-ups on your knuckles. You have a desire to go sit down rather than get punched in the gut again. You have a desire to haul off and sock that kid who just accidently kicked you in the groin during sparring. But you do not do anything to satisfy these desires.
When we practice zazen in the dojo, it's the same. You want to fidget, to move around. You want to sit in some easier posture than seiza or cross-legged. You want to look at the clock and see if we're almost done. But you don't. (Initially, you don't do these things because I will scold you if you do, right? Especially young students, but adults too! But eventually you have to internalize it if all this is going to work.)
When I was more of a novice in the budo, I'd look at my teachers and wonder how they overcame the boredom of repetition, the discomfort of physical training, the emotional impulses of despair and anger. I'd wonder when that stopped. What I've learned after 29 years at this is that it doesn't stop. They didn't overcome it, they just choose to not act on those impulses and thoughts and desires.
And that's harder, but also infintely more valuable. Because from this practice you learn the that just because there is a voice in your head saying "I want to do such-and-such", you don't have to do it. You don't have to eat that entire cake. You don't have to yell at that person whose behavior triggered your (justified or unjustified) anger. You don't have to buy that new consumer good whose ads promise that eternal happiness comes with each purchase. It's not reaching some bullshit fake state of constant inner peace where all those things go away, it's an ongoing process of choice.
It's not easy, because those voices are sneaky little buggers. But with practice, we can do a decent job of it.
Sometimes when the topic of desires comes up, we get the idea that we have to fight them, quash them. But that's not quite right either. Some desires are informative. Before his enlightenment, the Buddha damn near died from extreme asceticism, from ignoring the desire for food that was informing him that his body was about to collapse from lack of sustenance. Ignoring the desire to move your hand off of a hot stove you accidently touch means you get burned. Sexual desire is the red thread that creates us all, and though it's easy (very easy!) to get tangled in that thread, to disrespect it is to disrespect life itself.
And a desire that you cannot face squarely binds you just as much as one you cannot look away from. A thoughtless "no!" is just as bad as a thoughtless "yes!"
It may be a geek cliche but I think of a number of scenes in Star Trek: The Next Generation where Captain Picard has gathered his officers together to ask for their advice. (There were also such scenes with Captain Kirk in the original series, but the trope is more fully developed in TNG.) Worf always says, "Attack!" Troi always says, "Let's try to understand them and be friends." Everyone has their suggestion: you should do this, you should do that. Just like the desire-voices that come up in mediation or in training.
But Picard is a wise Captain. He does not try to silence any of these voices, he does not declare war on them. He mindfully considers their advice. He decides that Worf's aggressive approach isn't right today, but he knows it might be right tomorrow. He acknowledges that voice, thanks it for its advice, but he knows he doesn't have to heed it.
In a sense, we have to become captain of our minds, to learn to listen to the reports and advice of all the different voices of desire and fear and love and caution and attachment in our heads, and choose the best action. It's not an easy job. Perhaps we could say that meditation -- whether seated zazen or moving kata, kihon, and kumite -- is command training for the mind.
On the other hand, to speak of what meditation is...is to speak, rather than to do. If we think "oh, this is what it's for", then we bound to miss other aspects. So don't let your desire to say "I understand meditation" -- or "I understand karate" -- get you!