Dogs, on the whole, need a lot more training and attention. You set up a cat with a litter box and you're pretty much set; they mostly do their own thing.
I'm a dog person myself, and I think you get more out of them, but they're definitely an investment - you have to put a lot of effort and time to raise them right.
You've must have encountered some stupid dogs or something, or I just have awesome luck and seem to pick out geniuses. Even a friends dog, I'll take for a walk, within 5 minutes, it's no longer running ahead of me or anything, it's right by my side. Hell my best dog I've had, I've had for 14 years. He was the best dog ever. We could literally leave our yard gate open for days and go on trips (by accident of course), come home and see that he hasn't left.
I haven't had to do lots of training with a dog at all. All I do is walk them (which honestly, is what we should be doing with Dogs anyways and if that's considered lots of work... wow, I feel bad for the dog), do some tips I got from (funnily enough but they work) Cesar Milan (ie: sound, not letting them walk ahead, all that stuff), and boom, I've got them obedient. My older sisters a dog, a small thing, he was too hyper, so I took him for a walk, I kept him in line, whenever he didn't listen, he got a little boot in the chest (not a hard kick or anything, just enough to show him not to go ahead of me) and he was obedient right away.
I will say, I've had 1 good cat that was the best. It was at the farm I worked at. At first I thought it was a boy, so I called it Optimus Prime, then I found out it was a girl... and I named it something else, I can't remember at all. But she was a farm kitten (there's like 12 or so cats) and me and her instantly clicked. I could call her and she'd come running to get a treat. But then one of the fucking dogs killed her so I kicked the dog.