Honestly, my happiness with the size of my penis completely depends on what I am doing. If my girl and I are having oral sex, or straight sex, I love the size of my penis. If I slam it back all the way it causes her pain, so it ends up being perfect size. Also, any bigger and she wouldn't give me head. I'm 6.5-7 x 5.5...yes, she is a tiny girl.
Outside of sex, I wish I had a bigger penis for show. Thats just me being a normal guy I guess.
I just want to share one thing which means alot to me. If I had a bigger penis growing up, I would have had sex with more women. As it stands right now, i'm getting married on sat, and I have only slept with my soon to be wife. To me this is the best part of my situation.