Set theory was definitely my favorite course that I took in pure mathematics. It blew my mind how you can study “infinity” and find much structure; which I had

Set theory was definitely my favorite course that I took in pure mathematics. It blew my mind how you can study “infinity” and find much structure; which I had previously thought was a fairly vague concept. It doesn’t seem surprising to me now, but definitely did then. It might also have had something to do with the professor teaching the course, who was incredible.