When in a situation of conflict: Upset: assume you're the one in the wrong, blame yourself, not try to defend yourself, cry. (Or some but not all of these elements.) Angry: Assume you're right, blame the other person, argue back, yell. Or some but not all of these elements.

Obviously it depends on context. Some people have a very strong tendency to get upset, whereas others will sometimes be upset and sometimes be angry. I'm pretty strongly skewed towards getting upset; I don't like the experience of anger; but in a conflict with family members, I will frequently behave more angrily than upset.