“[Andrew] Granville, who is writing a book on analytic number theory, complained that Maynard has greatly slowed his progress. 'I’ve had to add about 150 extra pages because of him,' Granville said.”

Erica Klarreich with another lovely profile of an outstanding mathematician, in this instance number theorist James Maynard:

https://www.quantamagazine.org/james-maynard-solves-the-hardest-easy-math-problems-20200701/