Boy am I glad that this thread didn't exist when I first started agility!
When we first started training, Bailey clearly didn't want to do agility. She was fearful, sound sensitive, lacked confidence and drive, and was incredibly slow. If I would've read a thread like this back then I would've definitely considered quitting agility training. I wouldn't have wanted to push an activity on my dog when she hated it.
Thankfully, I pushed her because I felt that despite her fears, agility could built confidence and give her a much needed job to do. It didn't matter to me if she was slow and not drivey, but I did want her to learn to enjoy it.
There were days where I would just show up to class, get her to do one jump, praise her like crazy and leave. We always left on a positive note. And all our hard work paid off.
Bailey now loves agility. She doesn't want to leave class. She has gained a lot of confidence and really has a good time. She is still not the fastest sheltie, but I'm sure as her confidence continues to build she will get faster. Heck, I don't mind if she is as slow as a tortoise, as long as she is not fearful anymore.
My parents' dogs hate going for walks. They will walk so slow and clearly can't wait to get the dreaded walk over with. They would prefer to just stay inside all day, but like any dog they need exercise and will be walked whether they like it or not.
Dogs don't know what's best for them. If their owner thinks that agility is a good thing for their dogs (physical & mental exercise, etc), but their dog may not enjoy it as much as some other dogs do, who are we to discourage them from training and competing?
When I go to trials I am happy to watch every dog... the slow ones, distracted ones, fast ones or accurate ones. I am just thrilled to see people encouraging their dogs to be active and working together as a team. I'd much rather see a slow dog who is not really that interested on a course than a dog wasting away by sleeping all day with little to no exercise, which sadly is how most dogs live

.