Fun fact about Terence Tao: when getting his PhD, he almost failed his “general” exam, which is the most important test of your PhD. If you fail the generals you get kicked out. He was in his early 20’s at the time and expected the test to be way easier than it was so he studied pretty lightly and spent a lot of time, I kid you not, staying up late playing video games.
Even the smartest mathematician in the world once almost failed a test because he wanted to play video games.
Prof. Tao once walked to my linear algebra class on the first day of school thinking that he is supposed to teach that class. He actually had prepared a syllabus not knowing that it was not his class. The look on his face was priceless when the actual professor walked in. Later I took a PDE class with him. He is brilliant teacher. He loves math and teaching math and he doesn't do it for the money
Years ago when I was a graduate student visiting UCLA. I sat in one of his PDE seminar. I am deeply shocked by the intuition he demonstrated in that one-hour talk. That is the difference between fields medalist and ordinary smart people.
Even the smartest mathematician in the world once almost failed a test because he wanted to play video games.