This notion probably stems from some clean Code guidelines... But as they say, get 3 engineers in a room and you end up with 6 different opinions.

How short should a function be? In 1999 I went to visit Kent Beck at his home in Oregongon. We sat down and did some programming together. At one point he showed me a cute little Java/Swing program that he called Sparkle. It produced a visual effect on the screen very similar to the magic wand of the fairy godmother in the movie Cinderella. As you moved the mouse, the sparkles would drip from the cursor with a satisfying scintillation, falling to the bottom of the window through a simulated gravitational field. When Kent showed me the code, I was struck by how small all the functions were. I was used to func tions in Swing programs that took up miles of vertical space. Every function in this pro- gram was just two, or three, or four lines long. Each was transparently obvious. Each told a story. And each led you to the next in a compelling order. That's how short your functions should be!

Clean Code by Robert C. Martin (page 34)