I've Figured Out Women, Vol. LVIII

I think the key is to date an identical twin. Lavish the one you're dating with compliments about how beautiful she is. The whole time, never wasting a chance to tell her how ugly her twin sister is. So you get credit for being so sweet to your girlfriend, all the while she's thinking "what the...if he thinks my twin is hideous, what's that make me?" thereby shaking her confidence and keeping her under your thumb all that much more. Not rocket science. You're welcome, dudes and Ellen.