My personal reaction seems to be traceable to a potential vs achievement view of status.

Imagine a 10 year old who introduces himself and says he's been tested and found to be gifted/~150 IQ. My intuitive reaction is to be a little happy for the kid and maybe talk to him.

Imagine a 40 year old who introduces himself to the group and says he's been tested at 150; same IQ, same introduction, but my reaction is instantly negative - because why did he introduce himself based on his IQ? At age 40, shouldn't he have something to show for it, some personal identity beyond 'a smart person'? Be a doctor, a researcher somewhere, an entrepreneur, etc. His failure to mention anything more substantive seems like decent evidence that there is nothing better to mention, and he's simply failed at life - yet he still seems to think a lot of himself. An arrogant failure is not someone I wish to know or think highly of, and so I don't.