If you keep all the fish next time there won't be as many to catch. Nothing wrong with keeping some if you go on a fishing trip because that's the whole point but imo if you're fishing around where you live throw them back so they can be caught another day. Is the fight not why we fish in the 1st place?
Now, if you've ever fished in a pond where all the bass are pretty much the same size, 12-15 inches and nothing bigger then that pond needs thinned out. Keep some of the fish there, that's fine. They get stunted when the population gets too high. Who likes catching small fish, no one. We want the big ones.