why?!

why is it if you're having a wonderful day someone says one thing that's either negative or you don't like and your day just suddenly sucks? I'm not saying that happened to me right now, but it happens to me a lot... why is it that people HAVE to spread their bad day on you?? can't they keep it in their head and not have to say it? think people...darn it, THINK!!

I'm actually in a pretty good mood right now.. just wanted to throw that out there!