In Canada, one really popular brand of peanut butter is Kraft (which, apparently, is not available under that brand name in the US). As far as I know, peanut butter is equally popular (and equally sweet) in Canada and the US (but I've only ever lived in Canada). I doubt there would be as many Canadians who are Jif loyalists, though.
For mixing natural peanut butter, a long road trip seems to be a great solution. We use it to give our dog his meds and drove a jar from Ottawa to Quebec City to arrive to a perfectly mixed peanut butter. (I need to remember my own advice and bring a jar of natural peanut butter that needs mixing on every road trip I take!)
Personally, I am no PB or ketchup or mayo purist/loyalist. And while I can certainly tell the difference between maple syrup and table or other syrup, there are times and places where table syrup will do just fine. Ditto butter/margarine.
I certainly have preferences for certain things but I am having trouble coming up with an example of something where I'd rather go without than having to substitute. The current type of bra I am wearing is perhaps as close an example as I can think of but, quite frankly, if it wasn't for sales, I don't even know that I'd keep buying just this type of bra at regular price (approximately $60 a bra), let alone state that "no matter what" this bra costs, no substitute is acceptable. And I'm old enough now not to expect the marketplace to keep providing the product I've grown accustomed to. I know that this company could go under or change its line of products or whatever...and I'd have to find a substitute. (Sadly, going braless would not be an acceptable solution to having to go without this particular type of bra.) So, ultimately, I remain without an example. And, yet, insist on posting this anyway.