Yes, exactly, and there is the time commitment. If you're not getting paid, it can be difficult to rise to it. I'm sol under the circumstances, and yet I can't imagine shoving an entire manuscript onto someone, much less a stranger. That's asking for a slap.

For me, it's a matter of being grabbed by the premise at the very least, or the first paragraph. Hence the challenge of getting published, as I think the same applies. And it's luck. If i'm feeling less than generous, it's a no go. Then again, I'm not being paid to read manuscripts... though I think that doesn't always register in the minds of those who are.