This sounds like a recipe for stagnation. A true friend is willing to encourage you to grow.
I think I parsed that quote less along the lines of 'dude, you hardly know any math and so I won't love you' and more along the lines of 'dude, you seem to have the same taste for movies and music and we can have a conversation -- I love (hanging out with) you'.
The former has an objective measure and thus one can speak of definite growth while the latter is subjective.
Another monthly installment of the rationality quotes thread. The usual rules apply: