People become cops because they want the POWER! It's all about power. They love that they can bust some innocent person and make them pay hundreds of dollars for driving a little bit over the speed limit, spending THEIR hard-earned money on a prostitute, etc. They love that they can pull someone over, intimidate that person, use mind games to trick him/her into consenting to a search, and completely invade his/her privacy. If they get lucky, they might even get to arrest someone! WOW! Wouldn't that make them feel powerful and good about themselves.
Cops are just bullies who get into other people's business. They rarely do anything good. Ever had something stolen from you? Ever had a loved one in danger? Then you'll know that in truly important situations, the cops say, "Sorry, but there's nothing we can do." But when you're going just a little over the speed limit or double buckling in a car because there aren't enough seats... WOAH, now the cops feel the need to take some action!