The writer thinks that it's wrong to smile if we don't feel happy.
False. Why not control your emotions in the same way?
Some workers are taught to smile when they speak to people who can't see them.
True. The people who work on the phones are told to smile to their customers.
Eating chocolate has a more powerful effect on our emotions than smiling.
False. A smile can have the same positive effect on the brain as eating 2,000 chocolate bars.
You could stop a disagreement by smiling.
True. You can't stay angry, because they're smiling at you.
People who don't smile are more likely to get ill.
Not mentioned. It doesn't say about illnesses.
Other animals smile for the same reason as humans.
True. Chimpanzees do it.