Loyalty,I think.

*Note: It would be better to ask, "What do you think is your best personality trait?"

For anyone interested in reviewing some great ways to describe personalities, there is a list of 638 personality traits here: http://ideonomy.mit.edu/essays/traits.html

I think my best trait is also my worst trait.  I think I am benevolent but this personality type is sometimes regarded as insincere or simiplistic.

That is a difficult question to answer but for me I would say tolerance.  I mean by that, I am tolerant of other views and opinions which differ to my own. 

The world would be a boring place if we were all the same.  We need variety for life to be interesting. I love to meet new people and learn about their culture and language, it is what makes life fun.

What do you think is your best quality ?