OK so some selfish negative vibe merchant just had to bring the thread down; afraid it had to be me 
I had to mention the worst ones ever; ones that even a crisp-fiend like me find completely inedible (here's looking at you, Co-op and your Christmas stock). Walkers' Brussels Sprout flavored crisps. Yes really. But a horror far worse was Prosecco flavoured crisps. I expected them to be nicely salted snacks designed for eating alongside a glass of the stuff, but nope. They were flavoured to actually TASTE like Prosecco (and were unsurprisingly reduced to 20p a packet).
Most disgusting thing I think I've ever eaten!