can the science side of tumblr explain why >_> is more aesthetically pleasing than <_<

Westerners read everything visual, including signs with no words and art, from left to right and up to down. When the composition of an art piece pulls us against that, it makes us uncomfortable, and this also holds true for emoticons. Which is why (: is also weirder than :). It breaks the flow of the sentence.

oh there was an actual answer okay then