On being useful
Scott D. Clary writes in Facebook -- https://www.facebook.com/scottdclarypage/posts/pfbid02jUrT2EFJ1e9ZWZM8atF9aDEtByRpBoyHqKWvpgeKYGymHjoptE8MbPY7c1yfbtwjl :

The advice that changed my life:

"Stop trying to be impressive. Start being useful."

Impressive gets you invited to parties. Useful gets you equity.

Impressive is exhausting to maintain. Useful compounds while you sleep.

Choose accordingly.

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This advice presumes that you are going to be rewarded for being useful. In my experience, this is generally not the case.

I am a mathematician, I do not sell my services for money. In most cases, I do not see how being useful would serve my best interests, or the interests of advancement of mathematics which I am striving to serve.

As a general rule, I prefer to be impressive and useless. And no, I do not get invited to parties very much. Also, I decline most invitations.