Licking hands - I wouldn't say that was a bad habit. Some people say your horse/pony is lacking in salt/minerals and thats why they lick. One of mine loves to lick your hands, I see it as a sign of affection as she gives kisses too. Everyone has their own opinion though.
Head rubbing - This I find a little annoying. One of mine does this as soon as I dismount and stand near her head. Not only do I get covered in hair, I almost fall over with the force. Some people could see it as affection, whereas I see it as bad manners. :)