A deep desire to be looked up to as an elite crime fighter but reality teaches them how criminals are far more intelligent then they and their emotional level drops from glee to anger. So a new tactic emerges to keep their dream alive by concluding "I may not be smart enough to catch the real criminals, but at least I can take it out on someone I think deserves it." Hence the hero emerges and an ill-fated regular Joe goes to prison.
Airport Security has not caught one terrorist but plenty of innocent people have been effected by Hero Complex Syndrome" by harrassing innocent people who just want to get on the plane. When their patience is exhausted from witnessing this incredible security force who hasn't caught one terrorist, they become irate, and off to jail they go. Of course this would never have happened if security did their jobs in the background leaving honost people alone.