for fun:
why did you choose the breed/mix of the dog(s) you have?
(or why did you choose your future breed, that works too!)
Okay, 1) I physically can work with them, I can lift them if I have to, I don't need to maintain them daily, I can do all their grooming if I need to.
2) They're fun-smart. Constantly looking for entertainment, and keeping them occupied is highly enjoyable.
3) They'll tell me off if they think I am not offering enough motivation for something. It's really important to me that pets have a sense of self-worth & self-confidence that lets them determine a fair price for their attention & biddability.
4) They don't pester the horses. They don't want to herd them, they don't want to chase or bite them. They're cool with being buddies but if the horses are running, they get out of the way and stay still.
Oh yes, 5) they want interaction, lots of it. They'll be patient through a bad few days but eventually they're going to start insisting that I play again.