Sometimes we put ourselves down, not because of any outside force, but because:
1) Either we believe it ourselves, or
2)We believe someone else may be thinking it.
Either way, that belief of defining yourself negatively is not serving you, nor is it serving anyone else around you.
Where in your life can you consider either:
You are not the negative trait you say you are, or
You don't have to be impacted with what you believe others may be thinking about you.