Remind someone of your favor too much

Is there an expression to use when we want to say that someone does you a favor, but they keep talking about it or reminding you of it too much in a way that annoys you?

Solution 1:

harp on, according to the Free Dictionary

To talk about something to an excessive and tedious degree; dwell on something

In your example: "I wish X would stop harping on the fact he did me a favor when he drove me to work for a week when my car was in the shop."

The Free Dictionary gives the origin of the phrase:

This expression is a shortening of harp on the same string, meaning "to play the same note over and over." It was first recorded in 1518.

Harp on is probably more often associated with complaining incessantly, but it need not mean complaining.