Aside from actually looking at your account balances, that is!
For me, it's things like...
Passing a WOF
After years of expensive Warrant of Fitness checks (they always struck terror into my heart - our crappy car always failed and so it was never a question of whether we needed to sink money into it to pass the WOF, but how much). Since buying this car, that stress has totally gone away, and we only need to go once a year as opposed to every six months. It's such a great feeling to pass the first time around. And it still feels like a luxury.
Going to the movies
We're lucky that competition in our part of the city has driven prices down. Instead of paying $15 or more per ticket, we can buy tickets for under $9 at our local cinema! Even so, going to the movies still feels like a big extravagance to me.
As a kid we only ever rented movies from the video store. Even though new releases ($8 for overnight) cost more than a child movie ticket. (Sure, more than one person can watch it if you're hiring movies to play at home ... but it was only ever just me, as my parents aren't into movies and my brother was so much younger.)
Getting food delivered
Recently UberEats launched here and I got a $10 voucher to use on it. There's something so crazy indulgent about having a meal come to you without having to lift a finger (aside from tapping out your order in the app). I feel very strange about having a person rock up at my door with dinner from an outlet that's literally located just a few minutes away. Not planning to make this a habit, but a good backup for when you're bedridden with the winter flu potentially and can't rustle up real food for yourself!
It's different for everyone...This all stemmed from a random conversation we had the other day when T talked about how as a kid, a bucket of chicken from KFC was kind of a signifier of money - it's something he didn't see or experience until adulthood. And how in general they never had name brand stuff growing up. These days it's often important to him to get branded stuff if it's going to last longer; the flipside is that having grown up with cheap stuff that they weren't taught to care for or treat well, looking after the good stuff properly is not an instinctive thing either.
For me, if I go back to my childhood ... I don't think we ever paid full price for anything, so buying something that's not on sale sometimes still feels like a splurge.