Right at the start of this list, we saw some examples of beautiful young women making bold claims about their attractiveness. That habit apparently doesn't always end when youth does - sometimes, it carries on well into our later years; apparently becoming a lot more specific when it does so. Shirts that suggests you're more attractive than anyone else are ten a penny, but we're not sure we've ever seen someone state that they're precisely one fifth better looking than the rest of the population. How did she go about working this out?
There is a second possibility; she could just be complaining (or boasting) about how warm she is. Perhaps the shirt has a special layer of insulation which ensures that she's always 20% warmer than anyone else who's just wearing a standard t-shirt. If she's too warm, though, she shouldn't be wearing black. It's only going to make the problem worse!