It's just that some people suffer from a superiority complex, which warrants them to have an answer to every question and a comment to every subject. These like people hold the belief that, they are perfect and should be looked up to for solutions. However, this is not the case, because for you to know you should listen and learn from others.
Because they are related to the green hungry hungry hippo... you know the one that eats all those balls when ever it gets a chance to but never gets enough to eat because a) you don't give it enough chances to eat because you only play the game once or twice a year and b) its got to fight over what its given with three other hippos which are all also very hungry hungry.... you must know who I'm talking about. Anyway they are related through marrage because people who know it all are sons and daughters of Mrs Potato Head, and when Mr Potato Head passed away in that horrifying penguin attack, she remarried (less then 2 days later... slut) to simba (prince of the Pride Lands, born to King Mufasa and Queen Sarabi) who is uncle to the green hungry hungry hippo!!!! At the reception of Simbas and Mrs Potato Head-Malanatina wedding the green hungry hungry hippo poisened all of Mrs Potato Head-Malanatina children so they would think they would "know everything" in a revenge attack for not feeding him enough. Now for your own pretection you should go feed the green hungry hungry hippo NOW so you do not get poisened by him, resulting in you thinking you "knowing everything".