It is not important to work hard, it is important to be happy. Stop glorifying the act of working, please.
I strive for purpose, meaning, and positive impact. When I succeed, I'm happy. That drives how I pick my job and how I run my family life. The Frankl book "Man's Search for Meaning" makes a good case for this as a life goal.
I'm not going to my categorical statements like yours. But in my life philosophy, it's not so much important to be happy, as to be a good person and to have a fulfilling life.
But if other people have other values -- glorifying working hard for example -- it's important to respect that too.
Doesn't that mean that being a good person and having a fulfilling life is what makes _you_ happy?
This is something I think a lot about, and I know this is a philosophical topic that has been around for ever, but how do we call the state in which we're "ok" with our life? In your case the mental state when you believe that you're being a good person and having a fulfilling life? Is that happiness? Or is happiness a by-product of that state?
I believe this is what Aristotle called achieving virtue, maybe, it's been a while since I studied philosophy...
There's an even bigger difference in why you do things. If you do something because it helps someone (and that results in you being happy) it's very different than if you do the exact same thing to make you happy (and that thing also results in helping someone).
The philosophy I described is close to the philosophy of Aristotle or Confucius, albeit without the same rigid roles and social hierarchies which they use to define virtue.
But the mental state of being content where you are is another thing entirely. That's related to several Eastern philosophies (Zen and Buddhism especially), but it's very different from the American philosophy of striving for individual happiness, or the Aristotelian / Confucian philosophy of striving for virtue.
For many people it is attaining meaning, being and being seen as competent and useful, it is obtaining power or sacrificing oneself for an idea or their family. If you say that's all forms of happiness, then again that definition is pretty empty then.
However, there are many things which are important and which require hard work. Cultivating the discipline of hard work can thus be indirectly beneficial in a lot of ways.
And it's a sign as well: if you rarely find yourself doing hard work, then unless your life is exceptionally easy, you're probably missing out on something important.
And since hard work is a necessity, it's preferable to come to terms with it and develop the ability to enjoy it rather than hating it. For that it helps to draw satisfaction from doing it, which isn't quite the same thing as glorification, but it's still a way of putting it in a positive light.
Ultimately, if you define your own goals and do things for your own reasons, then hard work can fit in well with that. Just make sure your hard work is serving you instead of you serving hard work.
There's a reason that none of the major religions or ancient philosophers share this outlook. It's because a society that elevates the personal happiness of the individual above all else necessarily becomes self destructive.
That's because the major religions of history, especially the major organized religions, are part and parcel with their adjacent governmental power structure, and basically share it's interests, which mostly have to do with extracting value from the populace.
Plenty of philosophers, however, have spoken counter to this, from the Epicurians, to the Lokayatas, to Omar Khayyam.
I'm fortunate that I'm able to work hard in a career and field that also brings me happiness, so that's a bonus.