Fair point. Chasing happiness (esp. short term pleasure) as an end in itself, rather than as a side effect of doing valuable things, is unlikely to result in happiness.

But I think a strategic view of "what big choices in life will contribute to long term happiness?" is a still good thing to consider.

What does this even mean? Surely it's all relative, measured by our interpretation of what's great. I'm sure many theoretical physicists would consider their life work to be great, while many others would consider abstract theoretical physics with no practical application completely useless.

Personally, I aim to enjoy life and ensure that any children I have can do the same. I'm not sure if I'd see a point if there wasn't happiness in it for me. Fundamentally, we're fairly insignificant. Your interpretation of life is all you have. Why not be happy?

isn't thought about better world make you happy?