Games...

One of the most common head games that someone will play is "hot and cold" behavior. They will tell you "I miss you" then before you know it, they are backing out. They are dishonestly trying to keep their options open.

Rejecting your ex can lead to extreme resentment and they will do anything to grab your attention, even if it means indirectly. They will try to manipulate you into staying in their lives by acting like they resent you.

An ex that can't override their pride, guilt, or shame, so they reach out by mutual friends. It can be confusing and can lead you to second guess their intentions.

When the ex  presenting their life as joyful or exciting after the breakup,  they are doing it to make you feel like you are missing out. They remotely attempt to shove their new life, without you, down your throat.

The most hurtful head game is when your ex flaunts their new rebound relationship in front of you. It is just an attempt to bring you down and flaunt their new "upgrade."
You are forewarned.  Free at Last. Jast  a thought.