Oh, I think this outlook is a but sad! There's nothing "grown up" about going a shop/online and buying things new.
In fact in general I think it much more imaginative, exciting and planet friendly to be getting 2nd hand. Reusing where possible etc-
When I met DP he was firmly in the "I need a sofa, off I go to DFS, I need a bookshelf off I go to insert expensive furniture shop "
After hearing his past relationships and houses (he's had several fully furnished and left most them all behind) my mind literally spun at how many thousands upon thousands he must have spent, and all this stuff already exists and is being brought, sold, given away for free all over the country. I genuinely don't get it.
He is now absolutely on side with my way of buying - which is usually, I need a new XYZ, where can i pick one up from first - shpock, ebay, olio etc. Our house and style is now eclectic and interesting, rather than your standard out of the argos catalogue look.
Of course, I do think something should be brought new once the old is beyond repair- I usually source washing machines and hoovers new, mattresses too.
I'm honestly wracking my brains trying to think what was brought new in our house...
My under skin cupboard was a standard argos purchase, and I brought a new Tv 15 years ago - I still have that, our bikes were brought new and a few of DC Xmas gift Xmas just gone, for the first year ever.
Besides that, I cant think of much more.
I love second hand and think it's much more "grown up" to source things already out there, as your helping the planet, the environment, future generations- when I think of people who buy everything new (increasing demand for virgin materials etc) I actaully think of those who aren't educated in environmental matters and buy lots of things like fast fashion etc, prehaps 20s/30/40s - although that probably not totally true. Just what is in my minds eye.
Keep buying 2nd hand Op, it's a wonderful way to buy and absolutely no shame or not feeling grown up!