“Nice” is a treacherous word.
I actually can’t think of any other word that expresses contentment and acceptance while also harboring subterranean shades of doubt and pessimism.
Let’s make some examples.
Introduce a significant other to your family, and ask your parents afterward what they thought, if they respond “Oh, she is nice”, then they didn’t like her, at all. I talk from experience.
Nice is what you say when you’re skeptical and hesitant but you don’t want to offend.
Let’s take a different scenario.
Say your girlfriend bought a new dress that she is wearing to your date tonight. She spent the last hour or so in the bathroom getting ready — and by the way, women of the world: What’s going on in the bathroom? 60 minutes or more to get prepped? Really?
Anyway, she is really proud of the dress and she feels like a model. When she asks “How do I look?” you enthusiastically answer “You look nice!”
Ouch! You’d better run for your life buddy. You have just released the KRAKEN and you'll not get out of there alive. I want you to know that, I talk from experience (again!)