Crab Story

There was guy who wanted to go catch crabs, and so another guy took him in a boat with two buckets to the middle of some lake and said, "here this is the perfect spot to catch crabs."
So they threw down the net, and caught lots of crabs. They put the two crabs in two different buckets. The guy put a lid on one of the buckets and didn't put a lid on the other bucket, so the other guy asks, "well, why did you do that, the crabs can get away from that bucket too, so put lid on that one also" and the guy replies, "no, it is not necessary, that bucket doesn't need a a lid because every time a crab is trying to get out of that bucket, there are other crabs in the same bucket who are pulling him down, thus no crabs are going to get out of that, but the other bucket needs a lid because every crab that is trying to get out of that bucket, there are other crabs in that bucket who are helping the crab get out, thus each crab can get out with each others help, hence it needs a lid."