When I was planning my wedding, everyone warned me about "once in a lifetime" mentality, which is basically an excuse to spend money like crazy because it's a special occasion. This mentality doesn't just apply to weddings, though. It can hit during other occasions, too.
Photo by Stokpic
You've probably been there yourself. You fork over a huge chunk of money on something special and, since you've already spent so much, you think, "Eh, might as well go all out." Maybe you go on an expensive holiday and come back with souvenirs you'll never use, like the Empire State Building magnet I bought. Or maybe you go to a concert and you had such a good time that you decide to go all out and buy an overpriced T-shirt, poster and buttons.
"Once in a lifetime" mentality is why I'm fine with spending $25 on beer and a hot dog when I go to a baseball game. I've already spent so much on the ticket, and while it's not exactly a once in a lifetime event, it is a rare treat. And since I'm already treating myself, I might as well treat myself to the max. On the other hand, what's wrong with that? Beer and hot dogs are part of the experience for me. The thing is, I know this when I buy my ticket, so I budget an extra $25 for it. It's a conscious spending decision.
Here's another example, though.
Over the weekend, I went to a theme park. After spending a crazy amount of money on the ticket, I found that I was much more willing to spend money on snacks, drinks and souvenirs (and I don't even like souvenirs). I didn't actually buy any souvenirs, but I came close to it when I contemplated paying $3 extra for a novelty mug that I would bring home and never use. It was "once in a lifetime" mentality at play. How often do I go to Universal Studios? Rarely. So I might as well enjoy the hell out of it, even if it means spending money on stuff I don't need or even want.
The counterpoint here is that money is just a tool and you should be able to spend it on the things that matter to you. (Even if it is a $3 novelty mug!) That said, most of us don't have an unlimited cash flow. Spending money on one thing means not having enough for something else, so you want to make sure your spending matters and it's deliberate. This is one more behaviour to watch out for in doing that.