One can be perfectly content just sitting on the couch every day watching TV and living comfortably, having a good family, good food, and good friends. It really depends on how one is brought up - I know many people who are content living simply like that.
For me, a sense of fulfillment is key - fulfillment in every sense of the human being - mind, spirit, body, and soul. I believe humans are aspiring beings - they are quite goal-oriented and cannot function optimally without goals, no matter the extent. Knowing I have struggled for something and achieved it brings me great happiness. Also knowing I have affected another human being by connecting to them in some way brings me great joy.
The word contentment to me is very passive - it seems as if one needs to compromise something or settle for something to be content. Perhaps I have misunderstood. Well, maybe if one is content about one's bad situation, he or she has no desire to better the situation. That, I believe, is not true happiness.