Do Knowledge makes us Smart or Over-Smart?

Today I've met the guy who previously was on the same seat as I am right now (Senior Software Developer), The guy seems to be very knowledgeable or at least pretending to be one or not sure whatever the case may be, He was by the way called to solve a problem that he somehow previously has managed to solve but I didn't get how? anyway He entered with a huge bright smile on his face with a big black bag in his hand and wanted to show how much knowledge he has that can overcome any situation, sometimes this sort of behavior counts but I guess not in this situation, He was suppose to help us in solving the problem rather than showing off himself. Anyway he sat in front of the computer with great confidence or rather ordered me to do what ever he say which i did by the way, but nothing seems to work quite well or not at least according to his expectations. In the End he went by saying "Right now I am unable to memorize the solution, how I did it last time but I will try to do it later...!"

The only point I want to make is Knowledge no doubt is what makes you important or worthful and I really respect that guy no offense, no hard feelings but on the other hand if used wrongly will make you feel like a JERK !