Never Noticed: Science Fiction

The rattle and hum of the exhaust got on her nerves. Got on her mother-fucking nerves, you better believe it. Himself, he didn’t notice, of course. Never noticed a damn thing, he didn’t. Man could be getting mugged and he wouldn’t notice, not ‘till the mugger smacked him upside the head. Hell, he hadn’t even noticed when she had sex with his best friend on his own damn couch. Man never noticed a thing. So when he said, “What’s that?” she straightened right up.

Inspiration: the rattle of the copy machines
Story Potential: low. What's with all these low-potential entries?
Notes: It's a UFO! And white-trash protags! Oh, the excitement of it all!