Chandler made me paranoid about my own mascara goop
Remember when Chandler dated Joanna, and complained to Rachel about the mascara goop in the corner of her eye? Watching that as a kid, I was convinced that mascara goop thus must be THE most unattractive thing about a woman for a man. This feeling carried into adulthood, so much so that whenever I saw some mascara in the wrong place on my eye, I'd chide myself. And I'm STILL overly cautious about it.
This is ridiculous, I know, mostly because it's surprising enough in the first place that Chandler even knows what mascara is. (Joey, sure, but Chandler? No way.) But I couldn't have been the only one made neurotic about this from Friends, right? Bueller?