Heh, at long last, my grandparents and I have finished CLANNAD fully. As expected, they were confused at the end, and I did try to explain it. Grandma's pretty stubborn, but even though she is confused, she likes happy endings, so that is what she is believing in. I think they do like the story even if the ending threw them off, my mom and Nana still express it positively when it's brought up, and my little brother likes mentioning it.
So yeah, looks like I won't be watching CLANNAD with the family anymore now. I'll watch it alone from here-on out, unless I find out my future husband has never watched it. But even then, I'm pretty sure there will be more showings in the future. I'm still pleased with CLANNAD, I think it'll remain as my top favorite anime show for a long, long time.
Now if I can just get back into the visual novel...