Service, service .... I dunno, I'm a bit short on ideas here.
Sometimes I think I would like to be a college professor; push out important ideas into the world; teach & educate people, you know? On the other hand, many people on this forum seem to think that college is useless, a waste of time, a scam job etc. So whether being a college professor is an avenue for serving people is, I guess, a highly subjective question.
I used to be a deputy public prosecutor (or district attorney, in US terms). Work with the police; catch the baddies; prosecute them in court; make society a safer place for citizens and all that. Does that count as service? The job left a pretty sour taste in my mouth, in the end. I saw that many criminals were in fact victims too.