The recent death of legendary UCLA basketball coach John Wooden at 99 reminded me of a lesson I have learned the hard way. If you admire somebody and they are in anything remotely resembling close proximity to them, make it a point to meet that person even if you feel you are being a little pushy. I was at UCLA off and on for six years, during which time I went to Provo with friends for UCLA's first stint in the regional NCAA playoffs and came to admire John Wooden inordinately. But I never made it a point to meet him. He was gracious to everybody, so I'm sure he would have been gracious to me, and perhaps a friendship would have been sparked. But I didn't play basketball so I figured he wouldn't be all that interested in me.
I also regret not making it a point to meet Friederich Hayek the year he took a guest professorship at UCLA. I had already read "Road to Serfdom" and been influenced by it (and by Milton Friedman's "Capitalism and Freedom") in the direction of a libertarian worldview. So we would have had something to talk about. But he was teaching a graduate seminar and I was an undergraduate and I figured it would be pushy to call on him during office hours or to make an appointment. I deeply regret that because I never did get to meet him -- though I met Milton Friedman some years later and even developed a bit of a relationship with him, Rose and David.
Learn from my mistakes. Make it a point to meet people you admire when you have a chance.