Smoking
I don't understand why people still smoke.
They know all the dangers, they know it will harm them and the people around them.
Sometimes I come across people who are just not using their mind.
Like a pregnant woman nearby who told me she didn't mind that her child would be smaller than usual, so she wouldn't stop smoking. In fact, she said, she was helpign herself, because delivering a smaller baby would be easier.
Well, the brains of the child will also be smaller, with lesser chance of survival.