I can't tell if you are being serious or not. A lot of people who lift hurt themselves at some point, especially as they get older. It happens, it is usually because of not focusing on form and pushing too hard.
It's easier to hurt yourself on the machines than it is with free weights. Your brain/body won't let you try to squat way more than you can actually squat. If you can override this instinct and actually try to throw up more weight than you can handle, the way olympic weights work make dumping the weight almost automatic. You will embarrass yourself but won't get hurt. You should be using a spotter anyway.
However, you can load up a hip sled machine with way more weight than you should be attempting and destroy your lower back or knees. Personally, I believe leg press machines and their ilk should be banned. I know too many people with fucked up knees and backs from using those (myself included.)
Form is important, and not always intuitive.