Hi, I'd like to help you with your question.
People who feel they know it all are often insecure. They hide the insecurity by trying to show they know something about everything. After all, if they know everything, they must be very smart, smarter than everyone else. This makes the know it all feel secure.
Challenging a know it all is usually not a good idea. You are essentially challenging their self esteem when you do that. And since they feel insecure, thinking they do not know it all is threatening to them and most likely they will lash out.
One thing you can do is to make them think you are asking their opinion. So if information they provide doesn't sound correct to you, then instead of saying "this is not right" tell them you need their help in making sure the information will work. In other words, question the source, not your boss.
Even if you do not agree with what your boss says, if it is not vital, let it go. Nod and walk away. This may feel like giving in, but arguing with him/her over non vital information usually ends up bad for you.
If you are working with others, suggest that everyone have equal time to express their thoughts about the discussion. Try to make it even. If you have to, present this as a positive for your boss such as the more information they have, the better.
Find ways to work out your stress. If your boss is at it again and you feel upset, try taking a break and walk around. Go outside if you can. Keep desk toys like squeeze balls or pendulums on your desk. When your boss drives you crazy, pretend the ball is his/her head. Using humor can make you feel better and fight off stress.
Resist the temptation of expressing your feelings to your co workers. You never know if one of them will decide one day to inform the boss of how you feel. If someone brings up how the boss is, say work is stressful sometimes or something equally as general. Keep your feelings for people at home, family and friends not associate with your job.
If you find that your work is suffering and you are beginning to show signs of stress at home, consider changing jobs, if possible. Sometimes the work environment makes doing the work too difficult. When that happens, it is time to find a new job.
I hope this has helped you,