I am pleased to announce that I have taken photos of the building you are charged with protecting. Initially, I acquiesced to your objections based on what you deemed to be necessary for "security," but upon further reflection, I returned and got the shots. Though I could appreciate your concerns if I was attempting to shoot on premises, I am unaware that you possess the authority to prohibit me from using my camera while I am standing on a public thoroughfare.
In retrospect, I wish I had managed to get a picture of you while enraged at my failure to comply with your demands. That would have been sweet.
What makes me sad about the whole affair is that when I explained what I was looking at and what I was doing, you just stood there, incapable of seeing and utterly uncomprehending. In an instant, it was clear that you had never looked up at the building you work in every day. And while I commend you for the professionalism that your single line of thought and bullheadedness suggests, I am very sorry that it came at the price of your curiosity.