I realized something a few days ago. Insincerity bothers me - not the people, at least, not really. It's the physical act of being insincere. This realization troubled me as well, because I realized that sometimes I come across as insincere. But I think I may have finally figured this out.
People lie every time they say something they don't mean. It may be something small, perhaps saying the dress looks marvelous when really it's hideous, or pretending to be a friend. It's a lie, plain and simple. Thinking one thing and saying/doing another is hypocrisy. But the hypocrisy isn't what bothers me. If I know someone is being insincere, I don't care that they've told a lie; I care that they deceived another.
Wait, wait, wait a second... Isn't telling a lie and deceiving someone the same thing? I would submit that they are two different things. When you tell a lie, people may or may not believe it. But deceiving another, masking ones' true intentions, is completely different. You've added yet another mask on top of the ones you already wear.
Yes, it's the deception that bothers me. Letting another person believe that you really are a nice person, that you care, that you're 'best friends forever', those actions affect more than just the insincere friend. Imagine what happens when the one being deceived finds out you don't really care; that you were a fair-weather "friend"; that you were just there for kicks and giggles. That's got to hurt. It's not the lie that hurts, it's that the person would try to deceive.
The victim of insincerity may not even know what hit them. Suddenly, the best friend one could want sweeps into their lives, and it's lovely. It's the ones who really need sincerity, warmth, and friendship that are hurt by insincerity. The ones desperate for others to care who are wounded. And it's these emotionally needy people who are often the easiest to dupe of them all.
That's what bothers me: The deception. And what troubles me even more? That the capacity for such duplicity is inside every single one of us, and we don't even care.