I think if we say "sloppy", (and I probably did somewhere up there but I'm too sloppy to go and look) we're implying that the speaker is lazy or careless in some way - it's about a mental attitude rather than any particular habit.

If you care enough about speaking clearly and being understood, you'll try to avoid anything that gets in the way of this. If, on the other hand, you think it's up to other people to work a bit harder at deciphering your meaning, and that as long as you say something like what you mean, they'll sort it out, that's sloppiness. It's also misguided, because sloppy enunciation and expression is often more ambiguous or downright misleading than the speaker realises, because they haven't stopped to consider how it sounds.

And - oh heck, I'll confess this but it can't just be me - as you get older and your hearing less acute,you become more aware of sloppy and indistinct speech. So maybe it's an old farts' way of categorising speech habits, but it's still quite valid.

Marje (no, dear, I said Marje, not Mars!)