If we couldn't make it out of the trees without being obsessive-compulsive, then might it not stand to reason that SF aliens who zoom around the galaxy in all the popular movies and TV imitating humankind would be the same? So, as well as being warlike, greedy, selfish and whatnot like all the stories would have us believe, lets explore their obsessive side.
What about the superior race that shows up to control the planet Earth just to watch what we'd do if, say, they changed the weather patterns or introduced a new disease. ("My blotnix are on the Americans to come up with a cure, Zacknar.") We've been given the butterfly-on-a-pin treatment in SF before but not so much of the ant farm.
What if they use Earth as the lab rats to test an immunization they want? How about the old 'we buried the Asian subcontinent in water because we can' excuse that humans are so fond of when trying out new toys like, I don't know, the atom bombs. A great Kliban cartoon from the '70's had a bunch of slob aliens stumble off a saucer with open cans of something in their paws saying, "Greetings. We're creatures from a 5th rate planet."
SF always runs too much to the warlike for their alien conflicts these days. A good old fashioned hand washing obsession for its own sake could make for some Roland Emmerich scale disasters.
We miss you, Doug Adams!