People who chew with their mouths open.

[Valigarmander]

Particularly adults.

I don't see what's so difficult about keeping your lips shut so I don't have to listen to you noisily masticate. inb4 masturbation joke

[DarkZero]

Indeed.

It also doesn't help matters when they try to talk.

[Jenocide]

Ughhhh...
Does loud soup-slurping fall in this category too?
[size=-2]What about salad slurping?[/size]

[Rainbow Dash]

I don't see what's so difficult about keeping your lips shut so I don't have to listen to you noisily masticate. inb4 masturbation joke

well you made the joke so there goes that opportunity

way to go joke killer

[Ace Mercury]

That's the point of the "in before" phrase. It kills the joke.

And, yes, it's stupid. One thing I don't like: when it's relatively quiet, you can hear other people chew. It's really unnerving, that moist squishy slappy sound (of course, the chewing sound I make is not creepy to myself). It's almost like "Hey! Quit eating, I'm trying to eat here!", but that doesn't make sense.

[1-up Salesman]

I hate having to tell younger kids not to, and then they just keep doing it. Braaats.