Do you sometimes (or often) say disparaging things about yourself, to yourself?
You know, you whack your shoulder against the door frame as you walk through it and say, "What a klutz".
You pass a mirror and think, "Lookin' a little haggy today".
A common word in a crossword puzzle that you should know just won't come to you and your response is "Better resign from Mensa, dummy".
We all say such things to ourselves from time to time. If someone said it to us we'd be highly offended, but we don't seem to mind insulting ourselves. It sounds harmless, but our brain - that literal little guy that takes it all as gospel - doesn't process it as harmless. If it's repeated often enough our brain perceives it to be true. Like a little robot, it doesn't get sarcasm.
So how do we train ourselves to stop this self- belittlement? I read an article somewhere (can't remember where. "Way to go mental midget"). See, it's a hard habit to break. Anyway, the writer of the article suggested wearing a rubber band around your wrist and snapping it every time you have such thoughts. Self-applied behavior modification.
If you're someone who doesn't talk down to themselves, wow! Good for you. For the rest of us, this might be a great experiment. If it works on self-deprecation there is no limit to the possibilities. Stop smoking. Swear off donuts. Don't buy that dress you can't afford. It opens up a whole other world!