The faults of the other person that are visible and keep coming to mind?
The temptation of Satan causes us to see each other's faults too well,
to keep thinking about them, to record them, and also to keep talking about those faults to others.
Clearly, the Bible teaches that love keeps no record of wrongs (1 Cor. 13:5)
and covers over all wrongs (Prov. 10:12).
"He who covers over an offense promotes love"
(Prov. 17:9).