Back when the original Indiana Jones films came out, I would have never imagined that one day we would let an aggregate score made up of other people's opinions emotionally impact our decision making, fandom, love of Indiana Jones.
Back in '84 most critics tore Temple of Doom to shreds and in '89 Last Crusade had good to mixed reviews and was largely slagged off for being a "Raiders retread." Did we care back then?
I think it's only natural to have our feelings/expectations impacted by other people's comments about something. If I'm at a buffet and a whole bunch of people tell me, "Hey, don't get the potatoes, they taste really bad," then even if I'd been excited about having potatoes with my dinner, my excitement would be diminished somewhat. I still might try them, but with less enthusiasm.
As for whether or not we cared back in 1984, well, I was 9 years old when TOD came out, so I don't think I was even aware of what was being said in the papers about that movie. Also, I was still at the age where I doubt I would have believed a negative review, anyway. I think that lasted all the way up until 1999, when I started hearing negative things about The Phantom Menace, and I laughed them off, saying, "It's Star Wars... how could it not be good??" And then I saw the movie and realized, oh yeah, it's actually not that good.
I'm still hopeful for DOD, but I'd be lying if I said my expectations weren't dimmed by the reviews. But who knows... maybe going in with lower expectations will work to my benefit and I'll enjoy it even more as a result.