A particularly unpleasant habit associated with food is that of coprophagia, or the eating of excrement.

"It was an unpleasant habit of his that he indulged all too frequently."

He sniffed his right index finger, that bizarre, slightly unpleasant habit of his.

He has unpleasant habits, like sniffing a plastic bag full of old milk-bottle caps.

I bathed this morning and I have no unpleasant habits.

For some reason he was sweating now and had resumed his unpleasant habit of cracking the knuckles.

Well, it has the unpleasant habit of biting and defecating at the same time.

He kept himself clean and didn't-as far as I am aware-have any genuinely unpleasant habits.

For all their unpleasant habits, they have a fascination my human companions lack.