Spring practice is chance for guys to show they can play, and that when they are called upon they can bring it. However, what you don't need to do is go so hard that you can't control what you do and risk doing something stupid (which you don't really want to do at anytime).
Like what Jonathon Mincy did last weekend in Auburn's spring game.
Mincy was playing defensive back and happened to read the wide receiver screen just right so he flew in and blew it up. In the process he left his teammate, Dimitri Reese, on the ground and in need of medical attention. He was penalized and ejected for the hit.
It was a good play on Mincy's part, just poorly executed. Too often these days players look to make the big hit rather than make a play (thinking they are making the big play in the process). Sometimes it works, often times they miss and it doesn't, and other teams you go too high, hit the person in the head and draw a flag.
There is a lesson to be learned here kids. Play hard--just not stupid.