I walked into the lounge earlier and my DH and and my dog were on the sofa. The dog looked like he was chewing something. "What's he eating?" I asked DH. "Nothing" replied DH, but he looked shifty when he said it. So I pressed a little bit and then DH said, sheepishly "It's a bit of sleep". When I asked for clarification, it turns out then my DH collects the crusty eye bits from around my dogs eye hair, and then feeds it to him. And he has been doing this for YEARS. Because the dog likes it, apparently.
This must satisfy the "unreasonable behaviour" grounds, right?