That's in large part of why girls are so bad at accepting compliments, they're given them very liberally by everyone.
That's not a good excuse though, for a complete stranger or someone you're not interested at at all it's fine to sluff off compliments. But if you're engaged and interested in someone you may not be aware of how lame you come across if you can't accept any compliment from anyone.
Not once have I. This is a blanket statement for anyone this pertains to. I've only met 2 girls in my life who did this but it's still annoying enough to discuss.
Don't assume things that were never said.
Then why dont you specify instead of... *points to topic title*