This taught me that businesses are out for themselves no matter how nice the people are. It then taught me that if I don't like somewhere, I will just outright look elsewhere and bail.
After being let go from my second workplace, I left my next one due to him promising me more money and then going back on it with another deal which sounded great, but actually sucked when I thought about it. He is a really nice guy, but such a shady businessman, so I looked elsewhere and then handed in my notice.
The workplace after that one wasn't any better, they wouldn't use GIT, worked on each site whilst live (no dev environment). I hated it, so I took a week off to search elsewhere, found something better and handed my notice in.
Also, I tried to push for better practices which the other devs loved, but my manager and boss just wouldn't listen and refused any of my input.
There's actually a guy in that workplace who is super nice, but has never been let down like I have so he feels he owes the company everything and won't leave. Whenever he tries, the boss will offer him more pay and then he stays. It's sad, because he deserves so much better. :(