a bus back that's just so wrong

Think of the stuff you do when you're on your own. Picking your nose, etc, etc...

Doing it public is weird. No one wants to see it.

Its the same with advertising ideas that you come up with in-house. It may seem relevant and interesting to you, but really it's private.

That's why this bus back is so weird. It's too private and comes across creepy to anyone but the person who's thought it was.

Good ad agencies can make your private ideas acceptable to the committees they serve. That is one of our skills.

This advert isn't intensely bad, it's just private.