I am going to tell you how I feel about people making a person they know their emotional dumpster.
There is no way to point them out in a crowd. But you will know them once they get comfortable with you.
If you do things with the best intentions at heart and it turns out the opposite than it was intended. It happens. But when you take you disappointment and dump it on everyone. It is unacceptable. Yell, cry, storm off but never dump. That person is probably beating themselves up more than you could ever do. But you put on them a weight of disappointment and anger just to let you free yourself from the pain.
I have seen this happen over and over again. I have experience it myself ,a few times.
My advice is to step away if you can. Pray to your God or Goddess for guidance and peace. I would not say I give unto god/goddess. That is avoidance and I do not recommend that. We all have to face our problems and deal with it.