The ‘I owe you one’ is a flawed favour reciprocator.
You see now it’s on the person who did the favour to remember who they did a favour for (do they have to start a log book?), plus become comfortable calling in favours (even the long time ago ones), and cash it in with an appropriate reciprocation level.
For example you can’t ask someone to travel halfway across the country to hand you the remote control from the coffee table.
What’s more there’s no guarantee that the other person will be able to reciprocate the favour when you call it in and they might have forgotten the original favour you did.
Better, I think, to hand over a small token of gratitude for the favour done and have the nice gestures squared off then and there.
Thomas Duggan 