Well, as much as I agree with you from a personal perspective, I'm afraid it is part of your job to manage your boss, just like it's part of your job to build your team, build yourself, build your product, build your users and build your customers.
Anyway I walked out due to interlocutor stupidity exactly once:
Random guy that one of ours helped (for free) a year
before barges in and asks to talk to the manager,
someone points him at me.
Guy: I *demand* to talk to you about what someone from
your team did last year. It's bad.
Me: Sure, I'm not familiar with the story as I took
charge only last month, and I'm in a pinch for some
urgent business. Your thing looks urgent too, let's
schedule an appointement at noon.
Guy walks out mumbling to himself.
Me : So how can we help?
Guy : you guys did this last year. We can't use it.
Me : what's the problem? Did something new come up?
Guy : I think the problem is that whoever did this is
incompetent.
Me : woah, I didn't expect I'd have time for lunch
today.
/me walks out, goes to superior, tells story, the next
day the guy in question gets shelved.