Granted it's not normally a big deal to have a Piper door unlatch, my
IFR instructor failed to close it properly once. It was about 15
degrees F and we were IMC when it popped open. Strong, very cold gale
through the cockpit, instruments began to fog over, and by the time we
found a place to land we were both shaking with the cold. Since then
I've always briefed passengers not to freak out if it happens.