Struggling Writers discussion

Have you ever been reading a book, or watching a movie\TV show and something ridiculously similar to something in one of your manuscripts pops up? A similar plot twist, setting, character quirk, etc? How do you feel about it when you do, and do you do anything about it?
There are some things that probably happen all the time. If someone has a fantasy story that takes place in a European setting, certain tropes based on history or cultural norms are bound to get used a lot. However, what if it was something you thought was unique, and you were pumped about coming up with it, but then you see it somewhere else. Does that matter? Do you change it? This happens occasionally to me and I agonize over what to do about it, which slows down my writing.
The only thing I've ever heard that could be applied to this as advice is the commentary Matt Stone and Trey Parker had regarding South Park. In their DVD commentary they said they had to get over people saying "The Simpsons's did that already." They made their peace with it by saying "The Simpson's have been on the air 20 years [at that time] and of course they've done everything. If we are going to be accused of stealing ideas, it might was well be from one of the longest running TV shows ever."
Does this Philosophy apply here as well?