I would have once upon a time agreed that "L'Avventura" was overrated.  I first saw it as an 18 year-old and thought it was the apex of boredom.  Then years later, I watched it again (Criterion DVD) and thought it was mesmerizing.  To me it represented my growth as a film watcher that as an adult I could appreciate its subtlety and what it did for film language at the time that it was made.  Then I showed it to all my friends, thinking they would hate it and find it deathly dull, and they (none of whom are huge film buffs) all enjoyed it and thought it was really interesting, admiring the effort even if they didn't love the result.