Delay before 'O' opens a new line?

Question

I\'ve noticed that, occasionally, when I use O (capital \'o\') to create a new line and go into insert mode, there is a short delay before anything happens.

Answer 1

It happens if you press "O" right after the Escape key, right? I always assumed it was because the terminal driver was waiting a bit to see if you were going to complete an escape sequence.