I know a man who is quite possibly the nicest person I have ever met. He couldn't intentionally hurt a person, even if he wanted to. The thing is his niceness has not prevented anyone from being hurt. Sometimes, nice just delays when the hurt happens. One thing that is certainly true is that sometimes not being nice is the kindest thing we can do for someone. There are the cliche sayings "you have to be cruel to be kind" and "kill them with kindness". This does not mean being kind and doing nice things until you win them over.
There is quite a difference between being Nice and Kind. Being nice is when you are polite to people and treat people well out of social etiquette. Parents often tell their children to be nice to others, to not make a scene in front of other parents or make them look bad. Being nice is about appearances and showing a certain face.
Being kind is when you care about people and act in their best interest. Kindness requires honesty. Sometimes you can be kind to someone even though you aren’t doing the nice thing and you can be nice to someone while being unkind.
I see in a lot of my friends that anxiety around being nice to people they interact with. Not necessarily that they dislike or hate the person but they do not want to be close with them. The nice thing is to entertain them and be gentle but the kindest thing in a lot of these situations is, to be honest, and tell them you don't want them to hang out or entertain them. There are polite ways to tell people that you aren't interested in having them in your life. This is a form of setting boundaries. Deciding where and how you spend your energy.
I see a lot of people wasting their energy pretending to be friends with people they just want to detach from, without realizing that both their life and the other person's life would be better without the nice acts. It might hurt the other person to hear at first but it gives closure and allows both people to move on and put their energy elsewhere rather than invest it in a dead-end.
There are a lot of people who have been taught to be nice in the world. Kindness is something that can't be taught. It's a choice to care about the other person and do what is in their best interest. However, it's also a compromise between what is best for both parties. It might hurt at first but it. Setting the boundaries will be hard at first but with practice, the words will come. Sometimes there aren't going to be the right words but there will always be the right choice for you and how you spend your energy.
Are you being Nice or Kind?
Who are you spending your energy on and why? Is it adding to your life or taking from your life?