(True Story Bro)Why are white guys so arrogant?

So when I was in school, I was working a little retail job on the side in the electronics department. I know a lot about electronics considering that is what my major was in. Any way so I'm helping this little old white lady with CDRW's, she wants to burn pictures or whatever. I've giving her the easy steps of how to get started, so shes not overwhelmed. Then my white co-worker comes over, and hes intrudes and starts telling the lady all about CD compression rates, and FAT storage on cd's and a bunch of technical shyt. The lady is looking at him like WTH? Then I continue my expertise and she's like oh thank you, that was so simple. The white guy gets pissed and is like, don't think you know more then me. This azzhole really thinks I"m about to have a dic comparing competition working a retail job. Why are white guys like this? Why do they get pissy when there isn't a need for them? This seems to be the case every job where I work with white people, some days I'd rather do all the work myself, then have to work with white guys.