Another from chemistry: "small dangers are still dangers, don't underestimate them".

This was in my first uni. The person saying that mentioned how he never saw students harming themselves with cyanide, nitration solutions (sulphuric+nitric - highly corrosive and explosive) or the likes. No, it was always with dumb shit like glacial acetic acid skin burns, or a solvent catching fire.

Reminds me that this is the same logic I use on the road.

As a motorcycle rider I've become a very cautious car driver.

I'm a paranoid driver and I always assume that people on the road are always going to do something stupid. I'm wrong most of the time and I don't mind that but whenever I happen to avoid an accident because I was too careful, it reminds me why I'm always paranoid.

A girl in my chemistry class learned that the hard way. I have never seen a burn blister form so fast.