I don't care per se, for example I don't have a clue how much I can barbell bench of barbell OHP because for me they're not the best muscle builders. However, growth is a process in which you stimulate, adapt and grow. If you used 100kg on a certain exercise for 3 sets of 6 for example, the musculature will be stressed by that initially and will grow bigger and stronger to adapt to that stress. If you then go and use that same workload next time, the muscle has already adapted to that, so why would it need to adapt again by growing? You have to make it harder (at least,it appears harder on paper) over time to keep forcing that adaptive response.