So when you say "we" are made to feel bad, what exactly do you mean? Do you mean your wife feels bad and you'd like to persuade her not to spend more? Do you mean you feel bad and want more nice things than you currently have? Or do you mean your friends are often bragging or coming across as though they think they are better than you because they have nicer things?
If it's the last, the answer is simple: your friends are doinks. You need better friends.
If it's your wife, then maybe she's been going along with what you want and is feeling like she's missing out on some of the YOLO stuff she wants. If that is the issue, read the "50 ways to convert your SO" thread, and while you're working on that, negotiate a compromise that lets her spend a little more on those nice things she wants.
If it's you, then first of all, know that that's normal. Yes, there are some people -- many of them here -- who honestly don't give a shit about material stuff or social status. But most people care to some degree. We're just programmed to want the ShinyPretty. Yeah, sure, it's society and marketing and all that, but it goes deeper than that. When you have birds growing giant colorful plumes and animals growing giant showy horns, just so they can attract mates -- and when that entirely stupid and unnecessary show is actually tremendously successful over all recorded history -- there's some sort of deeply-entrenched programming going on that makes us susceptible to the big, showy, and impractical.*
The good news is that we are capable of higher-level thinking that most animals. So unlike those animals, we can feel tempted by the BrightShiny, and then still decide that however pretty it is, we don't need it. In fact, I was just having this talk with DD the other day, as she was deciding whether she needed a new pair of tennis shoes or a new wallet more, since her budget didn't extend to both. She really put a lot of thought into it, and I told her after she had decided that I was proud of how she worked her way through it, because no matter how much money you make, there is *always* going to be something you can't afford, so you're *always* going to have to make a choice.
So how do we do this? Well, here's what works for me: I tell myself I can have it if I want. That's it. Of course, there are costs to that as well. I mean, I could go buy a giant new house any time I want; I'd just have to go back to full-time work to afford it. So I remind myself of that, too. And then I think through how much I really want it, given those conditions.
Usually my desire for ShinyPretty is completely divorced from reality -- that is, I want the ShinyPretty, AND I want my current lifestyle and giant firehose of free cash. In other words, I want to win the lottery, so I can have it all.** But when I bring that fantasy back down to the real world and frame it up as a choice, I almost always find out that even though I want the ShinyPretty, I don't want it enough to pay the price for it (either financial or lifestyle).
*Total frolic and detour: I think with animals, the whole point is that their showy thing IS impractical. Because the signal they are sending is that they are so healthy, they have access to so much food, that their body can afford to expend the energy to grow this massive thing that is also entirely useless, so just imagine how strong their offspring will be.
**Would probably help if I bought a ticket, though.