Whether you are performing a fast lift like a clean or a slow lift like a curl, you should always be in control.  If you feel like the weight has you and you don’t have the weight then you are going too heavy.  If you feel like for some reason you are unstable when lifting then you need to evaluate your technique and your program.  You may need some specialized exercises to work small muscles that may be weak.  Remember that your body will always try to take the easy way out.  You have to make it do the opposite in the gym.  There is a difference between pulling yourself up to a bar or doing a pullup to increase back size and strength.  You have to be in control.  Are you pulling with your back or using your arms more?  Do you go all the way down and let your back stretch?  Can you pause on the way up, at the top, and on the way down?  If you can’t do these things then you aren’t working out a muscle as much as working a movement.  Cleans, snatches and the like and movements that we train.  Exercises like curls, pullups, and pushdowns are to train muscles.  Know the difference and make sure YOU are in control and not the weight.