Everyone except one was unlike all the others in some respect, so the one that wasn't unlike all the others was unlike all the others in that it wasn't unlike all the others.

Or, for those who prefer the Readers' Digest explanation, it was least like the others because it was the only one that was like all the others.

I'd be interested in seeing a concrete example, Faldage.

How can a number of things, each of which are different from each other, be the same as one other single thing?

A shopper with 3 different purchases in her arms could be the same shopper earlier in the day with 1 or 2 purchases in her arms, but with 3 purchases she is not the same as herself with one or two or none.