Loose fit on purpose = good.
Loose fit by accident = bad.
I've got a soft spot for dachshunds. My folks own a little (not mini anymore) long hair dapple and my neighbor has a local celebrity dachshund as he hurt his back, ended up w/paralyzed rear legs. He now gets around fine in a little wheelchair.
Lastly, our own little guy Brutus, a pug/beagle mix.
The pug provides him with the black mask and the worst teeth/underbite .
And the beagle allows him to run like the wind.