I believe it's a major turn off. No one wants to spend time with an arrogant person. They're not only asshats, but usually end up being liars and/or con-men.
Read the definition and decide for yourself:
The act or habit of arrogating, or making undue claims in an overbearing manner; that species of pride which consists in exorbitant claims of rank, dignity, estimation, or power, or which exalts the worth or importance of the person to an undue degree; proud contempt of others; lordliness; haughtiness; self-assumption; presumption.
Thanks all. It may just be that I get more contrary as I get older, but my tolerance for arrogance, pretentiousness and patronizing behavior is just simply gone.
Like most poor behavior the ability to post anonymously on the web seems to bring those qualities out in people. But I wonder if this also makes people more prone to develop these attitudes in their day to day lives. I've always said that if you look for insulting behavior everywhere, that is where you will find it. Now I notice it more and more, even when trying to ignore it.