Nearly two decades ago, a top mind in my field invited me to join him at his new department. I very politely declined, mostly because I’d already been in business for 6 years. I felt bad because he’s a great guy and, if you had asked teenage me what I wanted to do in life, it was exactly that.
Every now and then I regret the decision. Then I’m reminded… 
I’m guessing Peter Turchin doesn’t have a lot of fans here on the BBS? I can only find one post where his name appears. 
