is thanking the bus driver annoying
Bus drivers and personal drivers are not formal and always educated. Therefore a thank you letter for the bus driver or car driver needs to be casual and straight to the point. You can start with a casual hello or Hey and state the name of the bus driver. Since the bus driver does not need to be called Mr. you can consider him your friend and be casual. Start with thank you. Obviously there is no need to say anything else when you can just say thank you. Start your thank you letter by saying thank you to the bus driver for his services and help. If the bus driver is a regular driver, you can state a particular event or day to thank him for waiting for you even when you got late for the bus.