most common one I hear is "why do they suck so much"
this is always in reference to an experience someone has had with a suckass one that a school put in and never thought again about.
a: they don't. They're a superior computer, you've only had bad experiences with them through poorly maintained examples of typically Apple's most compromised, low-cost models.
Why do Macs crash all the time?
a: Again, a well-maintained one doesn't. Also, the new system software, Mac OS X doesn't require the preening and polishing to be stable... it just is, because it's based on UNIX.
Why don't Macs run Windows?
a: Because Mac OS is better than Windoze, they don't need to.
Why isn't there a Start Button?
a: There doesn't have to be. They didn't put one there when they designed it. It's different, get over it.
Why do you like Macs so much? Why can't you just be like everyone else and use a PC?
a: I use Macs because I value good design, quality, stability... and I hate Microsoft. I do, in fact use PCs. I have an HP notebook running Linux.
Obviously, some of the answers are my own personal responses, but those are typical questions I get. Although, I wasn't able to type the usually acidic and rude tone of voice. Why people that know nothing about a PC seem to hate Apples so much is beyond me.
Oh well, I hate people anyway.