Hello Mohsin,

clearly I'd say it is the power of perspective. It depends on how you interpret your personal situation, meaning what you focus on.

Let me explain:
Let's assume one is a millionaire.

Scenario a)
The person solely focuses on money and networth, since this is, according to his/her beliefs, what makes people superior, which ultimately is his/her goal - superiority.
Then this person will for sure be happy, at least for a time, then perspective and focus may change and the situation might have to be reevaluated.

Scenario b)
The millionaire focuses on relationships and bonds with other individuals (could even be the person from scenario a) after a while and a shift in focus). Therefore money alone is not what satisfies his request for healthy relationships. Hence, - if he has a bad reputation, shitty friends or no friends at all- he will not be happy, despite having a million $.

Luckily, a shift in focus can be done willingly. But most of the time occurs unconsciously.
You see, happiness is a matter of interpretation of the circumstances. For me it helps to consciously look at (=focus) what I have in life (family, friends, love of my life) - which is a great base to start conquering your goals, as a certain "base happiness" is set, boosting your confidence.
However, would I solely focus on the goals I want to achieve, without taking into account what incredible goods I already have, it would result in me being unhappy, as I usually fail in the first attempt of achieving my goals and worst of all: I'd likely neglect the ones I have and and am greatful for, as there would be no room for them in my focus, ultimately resulting in loosing them. That loss could later result in unhappiness, as focus could shift to loneliness, which I would then have to experience.

I hope this superficial answer gets the point accross a little bit, although I might have drifted off a little.
There are great books about this topic.

Best wishes