I don't know whether anybody finds this with their dh's, but mine can come over really unsociable to people + he can't see what the problem is!
He can be life + soul of the party if we've got a planned evening out with friends/visiting family for a weekend or people staying with us, but he seems the complete opposite if people call round unexpectedly! Doesn't happen that much as most people let us know if they're coming, as we do them.
Anyway the other day my friend + I had been out for the afternoon + she gave me a lift back, to save me taking the bus. She said, "I haven't seen your dh + the kids for ages, seems rude to just drive off", so I invited her in for coffee. To be fair, my dh was in the middle of preparing food for the dc's + watching a football match, but he just carried on with what he was doing, barely looked round, said Hi, answered if she spoke to him but didn't initiate any conversation with her the whole time she was here!
It's similar if my parents drop round on the way into town on the off-chance we're in, or if he comes in from work + I've got somebody here to pick up their child if they've been to play with my dc's. A quick hello, carries on as normal, changes out of work gear, gets a drink, etc.
I confront him afterwards + he can't see he's being rude, "I said Hi, I was polite!!", he'll say.
I admit I'm different, I'll stop what I'm doing, clear things away + make time for people, even if I'm busy. Dh says if people pop round unexpectedly they take him as they find him! We have completely different views on this.
The dc's are always full of chat to anybody who comes to the door which covers it up a bit, but I feel people don't know how to take my dh!