It's also a popularity contest. If they like you, they immediately merge. If they don't, they put the merge off indefinitely.
They also don't like to merge stuff from someone prolific, as the project's green blocks all shift over to that person.
Gotta fork. Only you care about your changes. Everyone else is focused on their own changes or clout-chasing a famous contributor.
Oh, thank you for your 2 lines of code, sir.
Let me lick your toes, sir.
*grovel, grovel, grovel*
