Example.

The Man who was very nice to you on *insert date, time place here* just went home and kicked his dog across the room.

But he was nice to you.

Just because someone is nice to you.... doesn't necessarily make them a good person.

edit to say: That's how those of us on the opposing end see it..... sorry if i have offended anyone by using that as an example. (and another edit because my first example was a bit too much)