The problems with being nice
Niceness is generally seen as something we all should practice. Here is a list of counter-points against being nice.
1. It is extremely egotistical. Many nice people are this way out of concern for their image. They are self centered and want to be seen as nice, so they act that way. It is purely them putting themselves on a pedastle and acting a certain way so that in turn they will be looked fondly upon.
2. It is demeaning. Nice people will frequently have pre-set nice behaviors. These completely ignore the personality of the person they are interacting with. They don't engage with who you are and respond accordingly. Instead they dismiss your complexities and overlook everything about you, in favor of the behavior that they've already decided they will practice.
3. Building off of #2 it is often extremely unwanted. People are misled into thinking a person wants friendship or romantic partnership when they don't. And also are given things they don't want, or in some cases may get in the way of what they do want. It then puts a burden on them to respond with gratitude to a kind gesture, but in actuality are now in a worse place than before.
4. It provides no information about the person. Like the first part of #3 the person's tastes are obscured. As the other person it is very difficult to gage their mood, interests, opinions, passions, or really any non-superficial thing about them. We aren't given the array of reactions that give us the information on what bothers or pleases that person.
5. It is belittling. It implicitly tells the other person they are incapable of dealing with rejection or displeasure. Pretty straightforward.
6. It is lazy. This reduced and robotic form of interaction while in one sense is quite burdensome on the nice person to maintain, also shows an emotional laziness to look at themselves and become a developed full person.
While obviously I am not saying you should be mean, I would say instead you should be yourself.
Niceness is a learned behavior, we should instead be true to what we are feeling.
OR if you still want to be truly nice, you need to learn who people actually are so you can do what is nice for them. This is nearly impossible to do with a stranger.