Putting Vinegar on your French Fries instead of Ketchup??? 
It was different to me but I found it unique and enjoyed it. Every once and a while I grab a bottle of Malt Vinegar and splash it on my fries to the chagrin of my cohorts.
I discovered this when the wife and I took a tour all the way around a lake. Lake Superior. We went to a little place to eat and when I got my order of burger and fries I was a bit surprised to get a handful of vinegar packets instead of ketchup. I asked "What's the deal with this" and the waitress said "Oh, you must be Americans, EH." 