If I asked my colleagues to describe me, I don't think that "optimist" would be among the first terms they'd use. I detest bullshit. I insist on calling out failures and I avoid sugar coating mild achievements as true success. Those who spend a lot of time around me wouldn't describe my disposition as sunny.
Underlying my gruff demeanor, though, is a deep optimism. I see sugar coating as cynical, a tacit admission that true success isn't possible. I see admission and examination of failure as evidence of a highly idealistic stance: learning and improvement are always possible. I love high standards because they represent a belief that high achievement is possible. I can't function without optimism. Whenever I lose my optimism in a particular situation, I disengage very quickly.
My boss and I had a good talk this week. He helped me see that, while my honesty is visible, my optimism is not. It's a good observation for me to ponder.