Here is one we know is true because Lisa Simpson says so! During the episode “It’s A Mad, Mad, Mad, Mad Marge”  while planning for the wedding Lisa expresses her concern;

Marge: Let’s see.. candles, flowers, place cards, rice…
Lisa: Oh mom, you’re not supposed to throw rice anymore! Birds eat it, their stomachs swell, and they explode!
Bart: Why am I just learning this now!?

Then in “Rome-old and Juli-eh” we have confirmation!

Lisa: Dad, don’t throw rice, it makes the birds swell up!
Homer: Oh, Lisa, that’s one of those rumors you get off the internet.
(Behind them, three birds explode)
Homer: Hey Selma? Want some rice?

So what’s going on? How have I missed the Youtube videos of exploding birds everywhere?! Turns out that rice needs water to expand. Even if the bird were to keep drinking water to make the rice expand it would take many hours and it doesn’t stay in the stomach that long,

So why aren’t we supposed to throw rice anymore? People slip over on it and get hurt… Don’t go getting ideas now.