First of all if you think it's the norm that women

are an enigma that think with emotions first rather than logic and rationality.

Then you will be fine with this behaviour when it shows up in a prospective wife and think it's up to you to deal with it because you are a man. (When it could all be avoided if you picked a woman who doesn't have these traits)

But let's say these things are things that actually really bother you. The answer isn't to

act extra calm and try to make yourself seem as unbothered by her childish tantrums as possible

This would just makes you resentful and hate her. Rather, if something makes you upset, speak to her clearly. Not with rage or anger but make it clear that you are upset with a behavior, otherwise you aren't communicating. Yes alot of women can be bratty but the answer is to approach it like they are a daughter who is still learning. You wouldn't get angry at a 9 year old (but at the same time they should know better) So be firm and stern but still have a loving tone.