If there is one single flaw that I would have to pick out in myself, it would be my inability to express love. It's not that I don't love nor am I a narcissist. I love very deeply, I just can't say it and hide my feelings with deep sarcasm and jokes. Now it might seem silly that all of this was brought on by a "How I Met Your Mother" episode, but when Marshall went through an entire episode of having to deal with the possible last words of his father, it brought up how I might feel if I knew that I would have gone 11 years without saying "I love you" to my parents and may never get the chance.
The last time I remember telling my one of my parents that I loved them was when I was 8. I last told my mom one morning as I was leaving for school and my dad when I was around 6 as he was putting me to bed one night. What if I never tell them again? I don't know how and I feel awkward even thinking about it. I don't hug my parents ever and I think that if something were to happen to them before I got a chance I think that would be the thing I would miss and regret the most.
I can't even show people sadness. The only thing people see is the sarcastic smart ass who's only emotional ability is to hide them. Maybe this explains my fear of commitment or maybe that's an entirely different issue on its own.