'What do grad students in maths do all day? Do they just sit at their desk and think?'
Absolutely in love with this answer by Yasha Berchenko-Kogan.
https://www.quora.com/What-do-grad-students-in-math-do-all-day-Do-they-just-sit-at-their-desk-and-think/answer/Yasha-Berchenko-Kogan