Misunderstandings.  At least for me, that is the case.

It is easy for me to forget that my wife is not native level fluent in English and some things I say are mis-interpreted or the other way around.

The best practice is to always try and consider what the other person means, rather than reacting to what they say.

Interrupting my girlfriend's yoga  exercise she does every morning. She typically plays music while she does it. If I touch her, speak to her or walk closeby her yoga carpet, she flips.

Last time she got so angry she picked up a chair and threw it against the floor, claiming I had 'inversed' her meditative flow from calmness to fury. I thought it was a very lucid self-reflexion.

parents ordering her to do stuff in the relationship that she does not want to do but feels she must obey her parents 

I'm French and TheMan is Italian and our most fights turn around him being late and me being a little too organised - of course, with him being Italian and all-. But we found ways to make it work over the past almost 10 years we're together, with the cardinal rule of all relationships : compromising! 

I don't get mad when his football socks are full of green plastic things from the field and get everywhere but he also tries not to be more than 15 mins late. If he is, i start ordering in a restaurant or leave by myself. 
Cross-cultural relationships do have nice tricks to them though...

Many fights and arguments in most cases are set off by missunderstandings, different sociocultural customs and "ASSUMING".......
It takes a bit of patience, speaking slower, and double checking to insure your idea or petition went accross and was understrood fully.  And respect the significant other customs, so in turn you can expect respect for yours.

Language misunderstandings which is why it's very important to always work to bridge the gap. One thing that starts arguments with my girl is that she doesn't yet understand English sarcasm, so my rapier wit is lost on her. 

Language and attitude difference combined can be a big issue. Par example; A couple days ago I was in the silk market trying to buy a shirt. I already bought one from this woman and liked it so much I was gonna buy one in a different pattern, cause it's so comfortable. I offered her 50 kuai hoping to pay 90 or so (what I did last time). The woman said "No, I can't give you that for 50, these ones are fifty."
Before I could respond, the wife is in there like a pitbull and the two are in an actual argument, not bargaining. So we walk away and I said "what the f#ck are you doing?! Why did you just jump in there like that? Now I can't buy that shirt!" So then she goes onto some tirade about that's how you have to deal with Chinese vendors to which I pointed out she was actually just being a bitch to the woman and now I can't buy that shirt at any price so obviously that's NOT how you deal with them... yadda yadda. 

I don't even know where I'm going with this, but I stand by the fact I was right.