Things I learned on my summer vacation from Slither about alien destruction karma:
1. If the people in your town are looking physically weird or behaving in a contradictory manner (for example, cleft palates and clergy really enjoying a cigarette) you (and they) are probably good candidates for alien invasion.
2. If you don't have sex with your husband, he will go take a walk in the woods where he will be personally invaded by an alien even if he doesn't want that because he's gotta get it from somewhere OK? Furthermore, you are declaring right then and there you will ultimately be with the other guy who's been carrying a torch since you were kids. Because not having sex on that one night does imply that entire choice.
3. Even an alien cannot resist the ideal American woman, who looks like Barbie, dresses like a suburban lady but still sexy, truly loves her husband and is in fact actually a good person (see fabulous Elizabeth Banks above).
4. Said alien does not count on above true love, and that will totally f*** him up such that you can get the chance to blow him up.
5. You do not need to be a big fancy scientist to figure out that you can just blow up an alien. Sure given more recent films one might say that it could create more spawn but sometimes you still these days can just blow them up so you might as well try that first when the chips are down.
6. Southern accents can be very sexy.