Clarity about expectations and deliverables is important, but deriving the lesson “don’t trust anyone”, and so much bitterness, is unnecessary. Life is very stressful if you’re constantly expecting to be betrayed and not making real friends out of lack of trust. You learned the wrong lesson. In my experience, an untrustworthy leader generates mistrust all the way down the hierarchy as people start to “look after number one” out of fear. The lesson for me is detect workplace toxicity early and get out fast. Sorry you had the experience, but not everyone is like that.