I have learned that you must first learn how to read your bosses mood before discuss anything.
Reality is that sometimes an unimportant issue can raise a conflict (most likely I wasn't able to read the mood) and your boss can end up using a bad selection of words such as "you'll sound like a retard" or "that's so stupid". Most likely I will read that as a personal attack and worsen the situation... after reflecting the issue and being out of the hype of the momentum, I realize that situation could have been easily avoided.
Solution: Stay Away! If you can't read your boss mood, avoid raising issues.
Any suggestions?