Only very recently, I've discovered the boundary that separates and distinguishes happiness from contentment. And, if I could choose between one of these two states, I would pick contentment.
This is because it is a state of being of acceptance, without the need to change or control anything - enjoying the present as it is, without wishing it was something else.
Happiness, at least from my perspective, involves a need for an ideal, which never really exists. This is not to say that we shouldn't strive for this ideal, but the idealism often coexists with a need to control, to hang on to a present state, where, in reality, events occur that may and do disrupt the present state. Also, happiness can involve the continual striving for improvement, advancement - a climbing of a figurative ladder. This can be greater 'success' in work, greater weight loss, a higher status or popularity.
Climbing the Ladder - where do the rungs stop?
These things are all fine in themselves, and I am not saying that they shouldn't be a goal, but when we depend upon them to feel we are okay and worthwhile, happiness can actually spiral down into emptiness, and even shame and continual self criticism.
My cat embodies contentment - she is not fixated on having to change anything. She just is. Likewise, when we practice acceptance, that level of feeling of being uncomfortable because things should be different, in our minds, tends to dissipate.
Cats teach us a lot about acceptance and contentment
She knows she is loved for being her. Likewise our true friends don't expect us to be pretty, successful, or have a perfectly tidy house. We are most likeable when we relax.
I am a self-admitted type c personality - ambitious, competitive and always rushed. Trying to climb some ladder or another. Comparing myself with others. Promising myself some unobtainable ideal I should reach before I'm 'happy'. But the more I let go, and just let myself be, the more likeable I probably am to others, as I allow myself time to truly listen and connect, instead of thinking about all the things I must do or change.
Realising you're not in control one hundred percent of the time and most importantly accepting it, feels uncomfortable at first, but once you go with it, you realise contentment is much more within reach.
Because happiness is a state we will fear will change, it can never be that comfortable. Because contentment is a reflection of acceptance, it naturally leads to one feeling more secure.