There is a difference between acting as if you know everything, and seeking knowledge while using the knowledge you have. I can't tell you (and you've probably experienced this yourself) how many people I've run across who have the proverbial answer to everything... people who know more than anyone else about a topic. These people have what is termed 'diarrhea of the mouth', and will continue to spout off about a topic of which they know nothing about. They are maddening to be around, because no matter what you do, or what you say, or how much reasoning you have behind what you say...they always have to "one up" you. Often with inaccurate statements which only increase the madness.
You would think that the computer age would decrease this phenomena somewhat, but I still see it occur frequently. People will argue about the darnedest things, especially Americans. There is, within the American culture at least, a lack of humility and an inability to concede to different viewpoints and ideas. We tend to accentuate the need to be right. About everything.
For those who are writers, this habit makes for some rich material when creating, writing and describing a character. We've all met these people and they can be the subject of one of our most irritating characters in a novel. For those who aren't writing, it's a cause of some major annoyance in life (OK, for writers it's annoying too). Regardless, when living each day... live fully and trust in your own inner wisdom and insights but share those insights only on rare occasion and listen more often. It may save you from pulling the black feathers from your throat in the end. While 'silence is golden', 'pause before speech' is wise.