Society's unwritten rules.

Sometimes people really like to give overly firm handshakes, and that is as annoying as when people give limp ones. Usually, when people grab too hard, it's because our hands have not fully met yet, and I'm not ready to start shaking, and then I'm sure my hand feels like pudding to them. When shaking hands, a person's hand muscles should have some degree of movement, since the whole hand is moving, and it is probably required for comfort adjustments.

I've definitely noticed the sidewalk lane thing. In grocery stores, lots of people completely ignore those laws, which you would think would appear more obvious since they are maneuvering carts around.

Jam it back in, in the dark.