I’ve had more than twenty bosses in my career. I worked well with nearly all of them. But surprisingly, I learned the most from the worst ones.

The truth is that most of my supervisors were average. Sadly, I really can’t remember much about them.

One was exceptional and became a role model. He took responsibility when things went badly. He gave others credit when things went well. He exuded integrity and became a close friend.

One boss was just plain incompetent. He was a nice guy but burned up and checked out. He couldn’t seem to do anything right. I think he retired mentally two years before the company let his body go. I was embarrassed to tell anyone I worked for him.

Two others were downright sinister if not evil. These were the bad bosses.

They could be kind and charming one minute and then—an hour later—mean, paranoid, and vindictive. Though I tried hard to stay out of the line-of-fire, they both skewered me on a few occasions.

Though I hated working for them at the time, I wouldn’t trade what I learned for anything.

Reality is that you don’t usually get to choose your boss. Sure, you can quit. But most bosses aren’t so bad that you would actually leave the company over them.

They are more like a low-grade headache. You learn to live with them. Besides, if you quit, you’ll miss some important lessons that will help you become a better leader.

Here are twenty random lessons I learned from bad bosses.

1. Everyone on the team matters. No one deserves to be treated poorly.
2. Bosses create an emotional climate with their attitudes and behaviors.
3. The higher up you are, the more people “read into” everything you say and do. Stuff gets amplified as it moves downstream.
4. A word of encouragement can literally make someone’s week. Conversely, a harsh word can ruin it.
5. Hire the right people then trust them to do their job.
6. Don’t ever intentionally embarrass people in front of their boss, their peers, or their direct reports.
7. Don’t attack people personally. Instead, focus on their performance.
8. Get both sides of the story before you take action.
9. Tell the truth; then you don’t have to remember what you said.
10. Give people room to fail and don’t rub their noses in it when they do.
11. Be quick to forgive and give the benefit of the doubt.
12. Measure twice, cut once.
13. Don’t ever ask your people to do something you are unwilling to do yourself.
14. Respect other people’s time, especially those under you.
15. Don’t believe all the nice things people say about you.
16. Follow-through on your commitments, even when it is inconvenient or expensive.
17. Don’t be ambitious to get promoted. Instead, focus on serving and doing a great job.
18. Be responsive to everyone at every level. You never know who may be your next boss.
19. Keep confidences. Make no exceptions.
20. Do not complain about your boss to anyone who is not part of the solution. If you can’t keep from complaining, then have the integrity to quit.

You can learn from anyone. If you don’t work for a great leader, don’t despair. Some of the lessons that impact you the most will come from the leaders who impressed you the least.