Self-Deprecation

--> tending or serving to undervalue or disparage onself.
--> trying to make yourself, your abilities and your achievements seem less important.
--> excessively modest.

Reminder to Self:
When self-deprecation goes too far, it can become self-loathing and self-sabotaging, which are less amusing forms of putting yourself down.
And when enough of it happens over time, you believe that you yourself are not worthy.