Constantly putting you down.

Your friendships should be equal. What you put in, you also get out. That means feedback, attraction, positivity, etc, making you both feel good. Toxic friendships tend to make you feel less than you're worth.

For example, they may draw attention to insecurities you have, and make you believe it to be true, they may discourage or discredit you, or tell you things that "they think are for the best" which will actually harm you.

They blame you for everything.

Everyone makes mistakes, it's human nature. However, good friends will apologize and in time solve the issue, but manipulative friendships often involve one person who will not own up to their mistakes. Meaning, it will always be you vs. them or blame situation.

Generally, you will be told that things are your fault, or you should change.

Attempting to control you.

Controlling friendships can seem less obvious. Having a friend's location seems harmless or pointless until they're watching your every move. Questioning where you are and why, or telling you what you can and can't do.

Purposeful humiliation.

Teasing and playing is part of every friendship but shamed in front of others to make you look bad, seem in the wrong or make themselves look better.

This is being abusive. This behavior won't change, they will not see the wrong and will often get defensive if you try to point it out.

Inconsistent personality.

Everyone has mood phases, and not everyone will always be in a good mood. However, this can seriously harm your mental health if you're always worried about fixing them.