because the only reason to do is to make your "likes" number ever so slightly bigger. for example most people see like 100 likes on their new video and think to themselves, wow! amazing ! this makes them feel happy and also there is a bigger chance that others will see your video now. but if you like your own video its just stupid and desperate
?? what are you talking about. If it's your own post, and you don't care about the numbers then don't like it.. Are you talking about liking someone elses post? if you click like on your own video because its truley funny and enjoyable is like rating the TV show you made 5 stars on netflix.. you don't rate your own creations. lol.
you can laugh, but the like button is a rating system you can vote up videos or down depending on quality and it's subjective to vote your own work, meaning you must be whoring for either a bigger like amount or desperate for more views. but you can do it if you want, im just explaining why most people feel this way