"In terms of the formation of long-term relationships, it's far better to get false negatives than false positives." - Eric Pepke
To me? I interpret that as... it is better for me to think of a close friend as "oh, not happening there" and have it turn out later
that actually it IS a good match and happening! (the false negative) Because you have already had a good rapport built as friends and it deepens into more. Gives you a better shot at a long term thing.
Than for me to go after a random crush person and have it turn out to be nothing past the initial crushy stages. (the false positive) Just not a long term runner because once the initial "pink fluffy lala cloud thing" wears off, there was nothing of substance to hold it together.
It's not that it CANNOT happen with a crush person. Just that the odds for long-term romance are better with someone you ALREADY have some kind of meaningful relationship with like a good friend.