I’m not sure how other languages handle this (probably similarly since humans are the same the world over), but we Americans tend to use some pretty weird words to show our affection.
For instance, when my dog is bugging me for attention, I’ll say, "You little creep."
My wife, who is Chinese and for whom English is a second language, keeps asking, "What does creep mean?"
When I tell her, she says, "Oh, so you’re talking about yourself."
Anyway, the point is that I’m using a put-down word–creep–as a term of endearment.