How do you tell if people will be good or bad friends?

It is difficult to learn that until you know them better. One way to tell is by listening carefully to their stories. Do they talk about people they used to be friends with? Why are they no longer friends with that person? Sometimes that will give you clues to their character. Otherwise, pay attention to their actions as you get to know them and then make decisions about the time you spend with them. It is important to maintain boundaries with friends and those who overstep your boundaries without concern or apology are not people you want as friends.