I believe you misunderstood what is meant in the dog training world as positive reinforcement (and I'm simplifying terms here rather than using technical dog training terms which can be a bit confusing). Positive reinforcement is giving a pleasurable consequence (food or praise) as a response to...
I too would recommend a herding breed from a working line such as the smooth coated Collie. (While the rough coated Collie would be a wonderful animal too, trust me, that coat is the fuzzy side of the velcro and takes a lot to brush out after a bath).
Collies are sweet tempered, alert...