What the mother did was a very bad approach. Like you pointed, if only she had decided to listen and dig more, the scenario all would have been avoided. It's always important to listen more and talk less. And for your incidence with the man, I'll say he really overstepped for you to really get angry bro. I can understand with your friends thinking so as well. There are many advantages to being quiet and watch some things happen before giving your take not just rushing in, as you've mentioned. And yes, your humility should not be that others would want to step on you.
Truly boss, questioning first is important and also not letting people take your humility for weakness is also very important.
@daverick thank you sir