Bounce fabric softener sheets
America is pretty big on tumble dryers, and while they do exist here, they're much less popular than they are stateside. Instead, the UK tends to opt for washer/dryer combos that utilize steam to (somewhat inefficiently) dry your clothes, or they use clothes horses to hang out damp goods and wait — sometimes even for days — for items to dry naturally.
It's a bit of a pain, to be honest. Back in New York, I used to throw in a couple of sheets of Bounce fabric softener into the dryer with my wet clothes and voila! Thirty minutes or so later, they'd be dry and static-free. Not so much the case over here.
Little Debbie snack cakes
Talk to any American expat living abroad and they'll likely tell you they miss Little Debbies, even if they didn't even really eat them while living in the US. Perhaps it's purely a nostalgic thing, but the absence of those little delicious snack cakes — Swiss Rolls, Nutty Bars, Oatmeal Cream Pies, and Zebra Cakes, in particular — makes me probably a little sadder than it should.
Aleve
Aleve, the brand name for the pain reliever naproxen sodium, is readily available over the counter in pretty much every American pharmacy. It's saved my bacon on multiple occasions, like when I had to wait several days for a root canal and when I threw my back out.
However, in the UK, it's only available by prescription. While I don't often take painkillers and save them for emergency purposes only, this is why whenever I go back to the States for a visit, I always stock up just in case.
Crest toothpaste
The UK has plenty of toothpaste despite the bad teeth stereotypes — and there are even some recognizable American brands like Aquafresh and Colgate. However, Crest has never made it over here, which is a crying shame.
The Crest toothpaste with baking soda and peroxide is pretty much my favorite toothpaste ever, so not being able to get it here is a shame. I'm not sure if some of the ingredients are prohibited or Crest just never had the desire to expand overseas, but I miss this stuff and need to pick up a few tubes on my next trip back.
Ivory soap
Again, there's no shortage of soap in the UK, even really good soap. However, if you're a purist like me, the fact that Ivory isn't sold here is a serious shame.
I've even been known to be so desperate for a bar of the 99% pure stuff that I've paid an exorbitant amount on Amazon for imported bars to be delivered to me. It smells amazing, it leaves my skin feeling great, and it even floats. What more can you want from soap?
LaCroix sparkling water
Again, this is something that's available at a serious premium via American import sites in the UK, but why it's not sold on supermarket shelves is beyond me. Admittedly, the UK is a bit behind the curve when it comes to flavored (but unsweetened) seltzers and sparkling waters.
Perrier and Pellegrino are easy enough to get a hold off, but the natural, sweetener-free stuff like LaCroix is only beginning to be seen as desirable, and the smaller brands which have launched a similar product pale in comparison to LaCroix in taste, price, and flavor selection.
Nabisco saltines
I don't know that I ate that many saltines when I lived in America, but I do know that they're delicious and aren't sold here even though they should be.
Again, the UK has plenty of crackers, many of which are really tasty even, but the closest thing to a saltine sold here is called a cream cracker, and it lacks the salty crumbliness of an American saltine.
Dunkin' iced coffee
Admittedly, Dunkin' coffee is not all that stellar. In fact, I can think of many small American roasters that are way better.
However, as a New Yorker whose apartment was literally down the block from a Dunkin' for years before moving, their Iced Turbos (iced coffee with an extra shot of espresso) were a part of my daily ritual that I really miss.
The coffee was hardly strong and the service at my local branch was always appallingly slow, but I can't say I don't miss it.