Very good point right here!
My thoughts are: When you were growing up were you given everything you wanted? Did you grow up in a wealthy lifestyle? I'm sure some people on this forum did. I did not. So, I don't feel bad one bit having to say "no" to my children for things that we can't afford or aren't willing to spend money on. In my family we got new clothes once a year when school started. I remember wearing shoes that had holes in them. During that time it was difficult because other children had newer clothes than me. But, looking back, I learned that "stuff is just stuff" and the valuable things in life can't be bought with money.
I feel blessed in some ways that we are definitely on the "lower income" side of the "expat" community (although my husband is local so we're not exactly truly expats). When we first came back to HK my husband made 10K/month--which actually is a pretty standard starting salary for many employees in HK. We know people who have started out at 8-6K/month. We had to live with my in-laws at first and then moved out because we needed to but our rent was really high at that time. Nothing like being pregnant with your first child, paying your rent and then wondering how you're going to take public transport to and from work and eat for the rest of the month. But we've never been homeless or hungry so we really are blessed. There are a lot of people in HK who can't say the same thing.
It's not always easy as we never get those trips that you're talking about--this year will be the first time I have been back to my home country in four years and the first time my son has seen his grandfather (my father) since he was an infant (he's now in kindergarten). My employer is paying for our tickets otherwise it's doubtful we would be going anywhere. Before last summer when my in-laws paid for the family to go with them to the Philippines I hadn't been out of Hong Kong on a holiday in three years.
But, for the very reasons you mentioned--the "keeping up with the Jones'" thing that is rampant in the expat community in HK (whether spoken or unspoken)--I find it really hard to relate to most expat families I meet (especially the ones who make a lot of money). I remember once talking to an expat mother who lived on HK Island (someone from Geobaby) and talking about meeting up for a playdate. I mentioned that I lived in the New Territories and she was like, "Oh, just take a taxi..." Yeah....taxi fare would be at least 300-500 HKD or more from where we live and to her that just seemed like a drop in the bucket. That's when I took a step back and just said, "Yes, we're just living in different worlds it seems." The lifestyles in HK are many and varied.
So, if you're hanging out with people who make you feel jealous and miserable, then look for more down-to-earth people who don't. There are people I simply won't spend time with--not because they're bad people but I definitely don't need any fodder to throw myself a pity party--I know myself so I just spend time with people who I understand and who understand me. You can always opt out of the "comparison game" and I felt a lot healthier and happier once I did!
You have to know yourself and know your family and what your priorities are. If your priorities are saving and living a down-to-earth lifestyle then it really shouldn't matter what other people are doing. That's the beauty of being an adult is you can choose.
Good luck with your adjustment to HK!