Why you ask?
Is there anyone else who get a better view and feel of one's own flaws and mistakes than thyself?
Oneself is always going to be the first one to take notice of one's own bad thoughts or feelings... Is this getting too confusing?
My point is... It is just natural to take notice of bad things over the nice ones, and your own mind works the same way about yourself.
I guess by looking it that way, it get's better to see why it is easier to don't like yourself than to like.
But what changes it all is that, besides the bad factors that everyone carries, we all have good ones. Not to mention that there are a few things that may look bad to you, but it's actually charming for others!
The real problem starts when you care too much about your problems and flaws that it ofuscates your bright side.
One must ask itself what really is important. The last time one cried, or the last time one laughed? This moment of weakness, or that moment of happiness?
These are reflections which I believe are essential.
I, myself, like everyone else, had my good and bad share of life experiences. When it all looked grim, I reached for the light in my own way. Be it through creating art, be it through listening or playing a music. What really matters is that you get to find balance within your heart.
Well... I didn't mean to say too much, but I hope my answer was satisfactory!