I've just had a chocolate craving and was delighted to find that DH has bought a multipack of Wispa bars today.
I just ate one. It was a tiny 25.5g. I don't think it was supposed to be "fun size". It was just a very small normal bar.
Obviously eating just one did not do the job for the craving so I ended up eating two. (and very nice they were). Because they are tiny though I have ended up eating more chocolate than if the bar has been a proper size in the first place.
It's the same with tiny packets of crisps. Hardly anything actually in them so you simply eat more packets. I'm hoping others think the same, or are you going to tell I am just greedy!