And you may not realize until you arrive at what used to be a far off destination.
Achieving goals and getting what you want does not ensure happiness. When the goals have been reached and have gotten what you set out to the quick realization that a lot was 'traded' or 'sacrified' to get here and a lot of time was spent striving for the ideal which only leads to more goals, more wants, more desires.
We will always want improvement and have the desire to create and find meaning, the mindset and attitude along the way is what determine your level of happiness and joy. Fulfillment is looking back and seeing how far you have come. Fulfillment is getting what you wanted. Fulfillment is realizing you did it! Yet this involves so many factors changing and re-arranging that to then sit in fulfillment and ask am I happy is another thing.
Yay, accomplished and somewhere long the line you grew to understand what else you want, so back to goal board. With a smile or with pressure. Happiness is not something you get, not something you do, it is a way of being. It being able to choose to see the bright side and make fun of the struggles. To look at the long road ahead and ward of stress and pressures with a smile.
Yes, there are chemicals involved and that is another story. What the question here is
"Can you be happy without the stuff?"
"Do you feel good without the 'thing', relationship or the surrounding circumstance?"
If you can answer this with a yes then celebrate because you are on to something!