The Real Reason Kakashi Wears A Mask In Naruto
Over the course of "Naruto's" 720 episodes, fans were introduced to an army's worth of characters. Shinobi hailing from the Land of Fire and beyond were fleshed out with sympathetic motivations and backstories to the point where it seemed like we knew everything about them. At the same time, however, there was one ninja who fans never quite learned everything about. For some reason or another, Kakashi Hatake remains somewhat of a mystery.
This is surprising, given that Kakashi acted as a central character throughout the majority of "Naruto." As the acting Jonin commander of Team 7, Kakashi was one of the earliest masters that Naruto, Sakura, and Sasuke had to help teach them ninja techniques. During that time, however, Kakashi never once removed his trademark mask in a way that would reveal his face to anyone. In fact, his face was hidden for so long that it became one of the show's biggest mysteries. But while we do eventually get to see Kakashi in the flesh, we never learn the real reason for why he wears a mask.
Only Kakashi truly knows what the mask is for
The odd thing about Kakashi's mask is that there was never a time in his life where he didn't wear it. Even when we see him in his childhood by way of flashbacks, the white-haired ninja is always sporting his signature face covering. This might indicate to some that wearing a mask is a tradition in Kakashi's clan or homeland, but nobody else in the Land of Fire wears one, including his father. This indicates that donning the mask is a decision that Kakashi made by himself as a child.
We can also eliminate the possibility that Kakashi is covering up any form of disfigurement, as he is revealed to be quite attractive on the rare occasion when the mask comes off. People who see his face are often completely awestruck by his natural beauty. Come to think of it, he might wear the mask just to avoid people's reactions.
The closest thing to an official reason behind Kakashi's mask comes from the non-canon "Naruto" spinoff series "Rock Lee's Springtime of Youth." According to the Narutopedia, an episode of this comedy anime reveals that he wears the mask to hide the nosebleeds he gets while reading his favorite book series, "Makeout Tactics." It's a common reaction that perverse characters have to suggestive material. Furthermore, it's as good of a reason as any for Kakashi to sport a mask every waking moment — even if it isn't technically canon.