100%, don't argue with your boss. Sometimes, depending on how they phrased a statement or proposal, you can present contradictory facts but never claim to have the answer.

Either the boss wants to hear your opinion or they don't. You need to look at body language, tone and wording to decide. In any case, they must decide.

Disagreeing in front of other employees is especially risky... It can work in your favor sometimes, but only if it serves the boss... For example, you might be providing the boss with an opportunity to demonstrate humility over a topic which they don't pride themselves on. If the boss switches and agrees with you, can improve your image in front of other employees and the boss gets to look like they are a good listener and rational decision maker. Everyone wins.

It also rests heavily on the boss' personality. Some people always have to be right, else they hate you.

> Either the boss wants to hear your opinion or they don't. You need to look at body language, tone and wording to decide.

Not everybody is adept at interpreting such subtle signs. A particular problem is when bosses say things like "Your opinion is appreciated.", "I value honest feedback.", blabla, but give different body signs.

In my opinion, this problem is less marked in Germany than the USA, because people tend to use of such sugar-coated lies much less in Germany.