If you make a lot of phone calls, just another thing to be wary of (if there wasn’t enough on your mind already) is; who’s hanging up first?
It’s always worth waiting a few seconds just to make sure they’ve finished speaking, that there’s nothing else, and yes, even that they’ve actually hung up. It’s only a few seconds of you time, but it saves an mistimed hang-up… just as your finger reaches for the “end call” button, you hear the faint sound of “Oh yeah, well I was… (click)”.
What message does that send? That you’re in a rush, in a hurry and you can’t spare a few seconds more for them. (I know that’s not true, but do they?)