Not trying to argue either way -- it comes down to defining "over" in this context. If asking a girl/boy out when she/he is going to reject you (but you don't know it) is overconfidence, then we need overconfidence. (We would need to be psychic or we'd never do anything.) If it means assuming every piece of contrary advice you receive is idiotic (eg invasion of Iraq) then no, we don't need it, and this is precisely the kind of definition the article uses.