What? Dilbert isn't being arrogant by sharing a good idea with a co-worker. Arrogant would be telling the co-worker's boss that the original idea is bad and then pulling out a better idea. Sounds like some fragile egos to me.
Well, after approx. 11 years of hearing these "spare time idea men/women" you develop other means to get along with them. Shoes are not that cheap to buy every day. ;)
If Dilbert is as arrogant as this strip seems to suggest and I was that co-worker......Dilbert would indeed have an extra shoe to put away that evening when he got home.