Low self-esteem is essentially carte blanche for everything from not
making the Math-o-holics to being nicknamed the "Earl of
Blow Jobs" to living a life of crime. Low self-esteem is an ideal
excuse, especially if you have a large schnoz or thick thighs, because
then it's more believable.
If you're good-looking, you're out of luck unless your parents got divorced or your brother got leukemia.
Positive people always look on the bright side and rarely see the worst
in people, which makes them miserable to be around. You can't trust or
have a real conversation with positive people, especially if you're not
slow.
On the other hand, positive people are the best to double cross or swindle out of money as they probably won't press charges.