Ooooh, this is a great thread!
Do Not take charge of the remote control in hosts house for the full 3 days and watch only ITV3 at max volume, leaving no chance for the host to reclaim the tv remote because you haven't moved your arse off the sofa and your grip from the remote since you arrived. Its rude.
Do Not moan about having to sleep on the 'bloody airbed' knowing the host spent £200 on said airbed especially for you so you didn't have to sleep on the perfectly adequate but 'too low' £80 airbed previously used... its rude.
Do Not tell host 'amusing anecdote' about how much DP sweats in the night and thats why he has to sleep naked in their living room and walk upstairs to the bathroom without even putting on a dressing gown... Its disgusting and rude.
Ahh.... that feels better!