When spending some time with your child and you ask if you can play too, you are actually teaching your child how to join in an activity. If you tell your child to ask another child if he may ride his tricycle, you are teaching your child to ask for his turn during play.
You teach your child how to show gratitude when you encourage him to say thank you for a treat. “You hold the bucket while I fill it with sand” teaches your child how to divide up work. If you tell your child that certain things make you sad, or angry, or happy, you are actually teaching your child how to express emotion.
Shouting to your child could frighten him, or, if repeated to often, what you are saying will simply be ignored.