You're missing the point. It's not a question of being desensitized, or owning lots of games. The Ms Pac he smashed was WORTHLESS. Even among collectors here (southern Ontario) many project cabs have been offered up for free with NO TAKERS. After months of frustration, the owners just smashed them up (one guy burned a cab) cuz they needed to get rid of them. If you can't even GIVE something away, what else can you do?!
I think I get it, I just never been offered a free cab, or seen a totally "worthless" cab (although I heard they exist). I do live in Indiana, which may have something to do with it. Nobody offers up free cabs here (that I'm aware of). I guess maybe if I had seen more of it, it would't be so shocking.

Also I've only been building/restoring cabs for about 6 months, and can't seem to find/afford the things I want (including a cab).

But, If I had the inventory/crap that guy has, I might try something flashy like that to get attention/marketing, if I had to make space.
Plus, I showed the video to my wife, and she said I should do the same thing to my current (10% done) project (she's so supportive)
