I think it's important to label our emotions accurately so that our children can better understand their own emotions. It's also important to display effective ways of handling our emotions. That way they can understand their own emotions better because we have labelled them. It will also help them know how to handle their emotions because we given them examples of what to do. For example, it's better to say, "I'm upset, I need some alone time," than it would be to yell and direct that negativity toward the child. Then if the child is upset later, they will more easily know that it's okay to be upset but it's better not to take it out on others.
I hope that made sense. I also agree that the key is to make the issue about the behaviour that was displayed and not the child themselves. Saying something like, "I love you very much, that's why I get sad when you do ______ ." is good. That way it is very clear that, while their behaviour was inappropriate, you still love them.
One last thing that I personally try to do is to avoid saying "you/it/he/she make(s) me sad/mad etc." It's probably because my mom said very often that it was my decision to be happy or unhappy no matter what anyone else did to me. Nobody can make me feel anything. It is my choice. To me, it gives a lot of empowerment. Thats not to say that I'm always happy but I realize that I do have a choice. My children can't make me upset. They can do things that contribute to my being upset but they cannot force me to feel a certain way. It's a subtle yet important (to me) distinction.