The last two times I used Samsung Pay weren't memorable; in fact I stopped using contactless over the reaction:
1. Rural gas station (had NFC capability but they didn't know apparently) I used my watch to pay, and they got angry, hit 'CANCEL' on their end (I saw the screen) and told me to get the **** out of their establishment as I was 'hacking' the system. Needless to say, I was quite upset.
2. Lowe's. I was using their self scan, and since the Galaxy Watch S3 Classic had MST, I figured it'd work. It brought down their entire payment system for ALL registers. Took 5 minutes to reboot, and alongside angry customers backed up in other lines looking at me, and the manager getting on my case about it, I stopped and just swiped like a peasant.
When you live where I do, trying to use the latest tech doesn't always work. There's stories on Reddit about those who get told to not use Samsung pay or NFC transactions by management since they don't get their money or something. Tons more assuming it's black magic (rural areas/technophobia are common), and many assuming outright that Apple Pay = Google/Samsung Pay.
The closest I get today is Walmart and Kroger Pay, which I use on a tablet that's offline unless I'm in a store. At least those two are open to technology and not so afraid of it.
Today, everyone uses chip'n Pin. You know, they stick a card in, wait like a minute plus, then it goes 'beep beep beep' like some master alarm from Top Gun, then they remove it. It's so slow, but that's about as new and open as the stores here get. I don't think I've ever seen anyone tap a watch or phone to pay without getting accosted much like I was.