There’s no question that once a person hits puberty, kissing becomes an obsession. But if you think about the actual act, it’s pretty gross. So why do we kiss? 

There are many hypotheses, but as Vsauce explains, the answer could be related to kiss feeding. 

Remember when popular actress Alicia Silverstone went viral feeding  her song mouth to mouth, mother bird style? By the way, that video stands with nearly two million disapproving views. 

Well, even though it looks and seems disgusting, there can be many benefits to kiss feeding. And before commercial baby food, the feeding format was a lot more common. 

Perhaps we were kiss feeding as a species for countless generations before better food alternatives were found. 

But that’s just one idea. Kissing is also very likely linked to the fact that important chemicals and hormones are transferred during a kiss, which, over millions of years, could lead to an evolved species like us that just loves kissing.