I tried to put "I am a happy person.", but it was marked wrong. In English if someone said "I am happy.", we would not think that someone meant "all the time, by nature as a personality trait.", perhaps if someone said "I am usually happy." or "I am generally happy." The English does not give enough information for us to understand what is meant by the Spanish. http://spanish.about.com/cs/verbs/a/servsestar.htm
If they meant "sometimes", then it would have to be "Estoy feliz." http://spanish.about.com/cs/verbs/a/servsestar.htm
I'm wondering why my translation of "I am happy" was incorrect, and "I am glad" was the given translation. I read the comments below and looked up the link on contento vs. feliz, etc. and now am very confused as to why one would ever use soy/ser for GLAD. In English gladness would not be used as an inherent irreversible character trait... Gracias.
"I am happy." is correct (At least now, I don't remember what this was like 11 months ago.), although it would not be considered an inherent character trait in English either.http://spanish.about.com/cs/verbs/a/servsestar.htm I guess if I am usually happy and I am happy again now, I should use "Soy feliz.", but if I am usually not happy, but I am happy now, then I should use "Estoy feliz." to show that change.
Maybe this will help: http://www.spanishdict.com/answers/243180/feliz-vs.-contento