Note re: mustard. It is not just an "other flavor," it is also an emulsifier!
It took me a while before I learned this. Even if you're not going for a mustardy flavor, a little mustard goes a long way in keeping the oil and vinegar from separating. Definitely recommend using some with basically every dressing you make.
This type of thing is the nominal purpose of credit scores, I believe. (Whether they're implemented effectively is another story...)