I don't think it's rude to walk out of a show as long as you don't walk out rudely... Wait for a blackout or intermission.
If you've paid your money and are not entertained, why stay? They get the money; you made a statement: We won't tolerate boring theatre.
Although I never found HIGH FIDELITY boring (which is why I didn't leave), I wasn't having fun.
The worst crime any show can commit is boredom. Some of the worst shows ever on Broadway have been some of the most fun fiascos. It's truly boring theatre that can warrant a walkout.
I walked out of HEARTBREAK HOUSE. I know the play. Didn't like what I was hearing, so left. If it's a new play, I usually stick it out. If they ever revive HIGH FIDELITY (hehehe), I'd walk out, unless they found a better way to tell a fairly dull story.
Bells and whistles can not improve on a dull story. Boy meets girl, she leaves, he gets her back. Classic story. Can work. FANTASTICKS comes to mind. HIGH FIDELITY told the same story set in "the last record store". In the book, that setting becomes a metaphor for growth. Didn't feel it during the show. No character (save, maybe, Dick and his "Tesh" girlfriend") held any interest for me to enhance that classic storyline or find any growth in their characters.
Yeah, it feels like the audience is having fun; then they forget everything. Nothing memorable. More manipulative direction and sound design in order to make this story work than any real dramatic tension and/or release.
It felt like an awkward date, or a dinner without flavor:
I got through it, but wouldn't eat there again...
"It's not so much do what you like, as it is that you like what you do." SS
"Time flies like an arrow, fruit flies like a banana." GMarx