What are examples of morally acceptable and morally unacceptable ways to express emotions?
There are as many examples of ways to express emotions as there are people feeling those emotions. Determining a morally acceptable or unacceptable way in which to express a given emotion is another variable to be considered, with the distinction between acceptable and unacceptable depending upon one's personal definition of what is or is not "moral" behavior.
Expressing one's love for another person by presenting a token of affection, such as a ring or other sign of commitment, is morally accepted in most cultures. Expressing love by painting a graffiti-style declaration on the pier of a public bridge is illegal and therefore morally unacceptable.
Demonstrating anger with another person could be done by confronting the person with a list of concerns or complaints that need to be addressed (morally acceptable) or by physically assaulting the person (morally unacceptable).