...make a mistake with the word begin?

Begin, began, begun, begin, began, begun, begin, began, begun, begin, began, begun, begin, began, begun, begin, began, begun, begin, began, begun, begin, began, begun... I have known this for ghod knows how many decades and still I always make the same mistake.

If it had been some other word, I would not have corrected it, but this fucker word "begin" has begUn to irritate me.