As in, the one that you have NO self control when it comes to eating it.
Mine is crisps, specifically salt & vinegar but tbh most crisps will do it for me. I can't just have one packet if I have a multipack, or part of a big 'sharing my bag. I've learnt through bitter experience that if I buy them, I will eat them until they're all gone. I have no self control 😞
Nothing else has quite the same effect, in fact I could quite happily go weeks or even months without eating many other things (chocolate, biscuits, etc)
I actually just can't allow myself to buy them anymore except very occasionally as a treat as I know I can't be trusted.
What really does it for you?