Is there a difference between "nice" and "kind" people?

I thought the two concepts are close relatives until Husenfulhu recently pointed out to me that actually they are not - although they appear deceptively similar.

It was during the middle of an Instagram chat that Husenfulhu said: "I'm not a nice person, but I can be kind".

I asked him to elaborate and he replied: "Well, nice people are like you know, they shake your hand, they're polite, they are generally easy to get along with, they'll hold the door open for you, but if you were in a situation and you needed help, they'll probably leave you (if they aren't kind)".

He added: "Being kind is offering yourself in the service of someone".

I then realized how important it is to identify the relatives, friends, colleagues, and acquaintances who steadfastly stood by my side in my dark times.