Sometimes this includes family. After spending years trying to make life better for my family I hit the breaking point. I care, but I just can't do it anymore. To love and care and bend over backwards with not so much as a fraction of the care or concern shown back to me I can no longer care the same. I am letting it go.
Angry, bitter, resentful, stressed out, physically maxed out, emotionally drained... all signs you are dealing with someone toxic but also where boundaries don't exist or have been overstepped. Chaos breeds where boundaries are absent.