Being nice is so obviously a good thing.
The fact is that you'd be hard pressed to get a single, succint definition of "nice". Courteous? Yes. Reciprocal? Yes. Well mannered? Yes. Not rude? Yes. Win-Win? Yes. Giving? Yes. Etc. Etc.
In public interactions, nice is synonymous with keeping peace, moving in unison, making things easier for everyone. This is absolutely the right way to conduct oneself in the world, if we want to move the world. It is the habit that many of us mold our childhood innocence into, to make the world a better place every time we practice it.
But the nice that I want to frame today is different. It isn't a quality, but more than that. Without offending all of us, it is safe to say that only a few people are this nice. Of course, some of these nice embodiments are given to you - parents, siblings and early childhood friends. Their niceness lasts a lifetime if you are gifted enough to tend them against the escape velocity that space and time separation places into the mix.
This other kind of nice is something you know because you simply feel it as a presence around these people. They are it. They make you feel - safe. With them, even if you are faced with a sheer face of a rock (of a problem), you know you won't fall if you let go. They are safety.
And curiously, you tend to ignore these nice people the most, because, like the air you breathe, you don't see them in that light every day. (that is indeed a shame if that happens often).
I have the good fortune of being friends with some of the nicest people of this kind. Some, I have had short interactions, but with some, fairly constant over time. Some are great seers, some are exactly like me - every day folks.
I'm deeply indebted to all of them - for changing me beyond what I thought was possible, all without advice or request or demand or force (in the order of typical escalation of expectations).