Noam Scheiber's profile of Larry Summers has been linked around elsewhere and I don't have much to add, except that I thought the MIT yearbook picture of Summers is pretty frightening, and that this anecdote was pretty funny:
Even as a young professor, Summers would attempt to restrain his own worst impulses, sometimes in poignantly ham-handed ways. Alan Krueger, an economics professor at Princeton, once earned a rare A-plus on Summers's public-finance exam. [...] When Krueger got the test back, he noticed that Summers had written him a note. "You've clearly mastered the material," it said. "I'd be interested in having you work for me." But the words "having you work for me" had been crossed out. In their place, Summers had written "working with you on a paper this summer."
For some reason I found this endearing.