We have no right to be angry when we allow others to cross our boundaries.
Our integrity is ours, not theirs, to maintain.
Of course, people who respect us will also respect our boundaries, but only if we do first.
On the other hand, people who do not respect us may never respect our boundaries, but they can be taught or made to not cross them.
If they cannot, the onus is on us to distance ourselves from them so that they do not have the opportunity to impose themselves on us or make demands of us that we cannot or should not give into.
If we do none of this, however, if we do not respect our own boundaries and maintain our own integrity, we really cannot be angry or upset when others need, want, or require more from us than we have to offer.
It is not their responsibility to know where our limitations are.
The responsibility is ours to make it known in as clear yet respectful a way as possible.