I'm with OP and MandM on this one. 80k doesn't get you very far in this city, might not even cover rent. 5k is also not a lot for dinner here and it's still a mediocre experience. You can eat at very nice Michellin starred places in Europe or the US for what you spend on an average seafood dinner here.
The unhappiness part is self-made though. I'm probably just as unhappy here as Op, but that is my own fault and I understand all the counter arguments saying the opposite. It's just difficult to find people to relate to here, especially if your social circle is mostly work related. Everyone always seems to want something out of friendships. I've been thinking about taking the pay cut and moving back to have a nice middle class life, normal friendships, normal blood pressure, BBQs, going to a nice museum etc. But I'd probably miss the life and travel opportunities here. The more time I'm spending back home the less I want to return to HK. But maybe I'm just getting old and running out of patience.