I rode my bike across town while a big storm was on its way, and I went to the water's edge to get a look at the storm surge. While the roads were empty, the waterfront was packed with people doing the same thing. Normally, I'd never climb over a police barrier or walk out onto a half-flooded pier, but when there's about 1000 other people doing it, it somehow seems like an acceptable thing to do. This is, of course, not the case. I did it anyway, fully conscious that I was under the spell of group-think, but also rationalizing that the police weren't going to be physically possible to arrest all of us.