I find it so interesting that the majority of things we can't stand about other people really turn out to be things we can't stand about ourselves. Most of the time, that's the case, but sometimes, it's also just a simple insecurity. For example, someone who becomes extremely annoyed with know-it-alls is either a know-it-all themselves, or they feel intellectually inferior. 9.9 times out of 10, it is one or the other.
Another great example is homophobia. How many times do we find out that public figures (like politicians) or pastors, priests, etc. who adamantly advocate against homosexuality end up coming out of the closet, or being caught rainbow (or red) handed in some big gay fun? To further back that up, there was this great study performed back in 1996 to further support the theory that a high majority of die hard homophobes actually turn out to be gay themselves. They showed three different videos to a control group of heterosexual men, as well as a group of self declared homophobic men (there was also a scientific scale by which their homophobia was measured). Each participant was shown three different sexually explicit videos... heterosexual, male homosexual, and lesbian... and without getting into too much detail, let's just say the right "reactions" were measured. Without question, the results suggested that homophobia is directly linked with homosexual arousal that the homophobic individual is either completely unaware of, or (in so many cases) completely denies. So, I suggest you homophobes think next time you feel like doing some gay bashing... some of us are "in the know!" lol...
Anyway, I can't tell you how many times I have witnessed someone become SO frustrated with someone else's habit or personality trait that they possess themselves! I've seen people totally fed up with others who are "dense" when that is exactly how I would describe them myself. Or a person that is ready to strangle a perfectionist when they are a perfectionist themselves. When you begin paying attention to things like this, it becomes really fascinating! You can almost always tell what it is someone hates about themselves when they go off on a tangent about someone else's personality.