I believe in physiognomy. It seems like a lost science that was done away with because it was probably seen as racist and it was seen as unethical. But I use physiognomy to measure peoples character all the time and its correct about 90% of the time.
I use it to identify people who are aggressive, people who would hurt me, people who are sociopaths. I use it to identify people I'd get along with, people who are nice, people who are smart. There's almost no limits.