Bit surprised at the Rhodesian Ridgeback being in the least aggressive list. It's a breed which used to require careful handling. Mind, the old Kennel Club handbook had "only for the most experienced owners" in its notes on the Hungarian Puli, and that's a herding sheepdog. Breeds do change with the breeding. There are certainly breeds which still require a lot more care in training and handling, though, mainly because they were bred as fighting dogs or for protection of the owner or property.These are more likely to be trouble for humans who come close.
The lapdogs and small breeds, like the papillon, seem most risky when they've been brought up as 'mummy's pets', and become so attached to the owner and vice versa that they're suspicious of any dog or person who comes close him or her. In the US, the American cocker spaniel is most frequently found to be aggressive like that, but it's also one of their most popular and numerous breeds.