My motto in yoga is the same as my motto in life: Work less, do more. OK, I actually stole that motto from of one of my favorite audio podcasters, The Get-It-Done Guy. But it's a philosophy I've adopted. Why on earth anyone would work more than they have to has always been beyond me. I mean, if you can accomplish the same task with minimal effort, that's the way to go. Plus, everybody knows that working sucks. The Get-It-Done Guy talks about how to get more organized and get things done faster so you have more time to play. I definitely need more play time.
In yoga, it's not about accomplishing something because there really isn't an end goal. But I almost always need to remember to work less... and let the pose do me. When you relax, soften, and go with the flow the body is more malleable and benefits more from the postures. (Trust me, I have learned this the hard way.)
I'm curious, though, which pose do you approach by trying WAY TOO HARD? For me, I think it's probably Utthita Hasta Padangustasana (Extended Hand-to-Big-Toe Pose).