Oh we know that.
 
 
Rainbow dash: “uh, what are you looking at down there?”
 
Me: “OH! Uh, nothing.”

@Jaredking203  

 
Oh yes, I’m not for a second saying that they don’t OFTEN wear clothing - but it’s not usual for the vast majority of ponies.
 
Any time there’s a major event - the Grand Galloping Gala, Twiley’s coronation, etc etc etc…or even to sing, for a fashion show, whatever, they’ happily get themselves all dolled up. But in the normal course of day-to-day life, most of the ponies just go about their business in their own horsehair coats, and that’s fine too. :)

@DarkyBoode32  
You would be asking what would MLP FiM be like if ponies didn’t wear clothes, wait.  
On second thought maybe you wouldn’t.

What would MLP FiM be like if ponies wore clothes all the time, like humans always do? It would probably be interesting.

@Yet One More Idiot  
Donald Duck was even stranger. He is almost always pants-less, but when he loses his shirt he suddenly realizes he is naked and covers his non-existent guy parts.

@Background Pony #4ED9  
@Yet One More Idiot  
Despite for the fact the “We normally don’t wear clothes” line has been rumored as true, this is false, as ponies do wear clothes on multiple occasions throughout all nine seasons.

The way the ponies react to nudity is weird if you stop to think about it for too long. They don’t normally wear any clothing, but when they do they suddenly get very squeamish about being underdressed… xD

Except those aren’t ‘clothes’ but absorbent materials applied to help hair dry faster.