I've heard it said before that when someone is violently opposed to or highly outspoken about something that he may take this position because of an unconscious (or perhaps conscious) self-hatred. Like the Republican Congressman who carried the banner against gay rights (was VERY opposed), and then it came to light that he was having a sexual relationships with male interns who worked for him.
Or the guy in my unit who is serving two life sentences for murder. He's proud of the fact that he killed two child molesters, and yet he finds the youngest guy he can in our unit to have a sexual relationship with. Self-hatred resulting in Life in prison? Maybe...
We can use our own irritations to shed light on our own issues. For me, I find that arrogant people really irritate me. I'm aware that arrogance is often a mask for insecurity, but when someone adamantly claims to be right 100% of the time, or acts as if they know it all, I don't want to be around them.
But I'm also aware that perhaps the main reason arrogance irritates me so much is that I too can often be arrogant. So, while it's not necessarily a given, being aware of your own triggers or irritations can reveal "blindspots" about yourself that you might not have known or perhaps have been suppressing.