Press It Yourself

Passing an office building late one night, the blonde saw a sign that read, "Press bell for night watchman."

She did so, and after several minutes she heard the watchman clomping down the stairs. The uniformed men proceeded to unlock first one gate, then another, shut down the alarm system, and finally made his way through the revolving door.

"Well," he snarled, "what do you want?"

"I just wanted to know why you can't ring it yourself."