Tadano as a person is so plain and unremarkable, but he has a big heart and natural talent of complimenting and finding good traits out of a person that sets him on the striking range of most people.
The kind of dude that gets girls not because of his looks but because of his charming attitude.
When you've been an average person in all your life, averaging in almost anything, you'll develop a sense to observe other's weaknesses and strengths (using yourself as the basis)