He sems to have anoyed you?
Theres nothing worse than seeing someone doing something all wrong and not being able to help them. Mind you most of the time people don't want help.
To be honist if someone came into my room and started telling me to do this differntly and that better, I would probably get a bit up set.
That said, I would still lissen to them and later when i was all alone I might check it out on the internet. I gess it's all in the attuide.
The tin foil thing is really anoying though, and when you tell someone, they just pretend like they didn't hear you. I gess it's beacuse it must take, like hours to stick it all to the wall.