Which of the following scenarios is inappropriate according to email etiquette?

Using several emoticons in a client email is considered inappropriate according to email etiquette because it can come off as unprofessional. In a business context, particularly when communicating with clients, the tone of the email should maintain a level of professionalism and clarity. Emoticons can undermine this professionalism and may not be interpreted well, potentially leading to misunderstandings about the sender's seriousness or intent.

In contrast, thanking a colleague for a birthday card with an emoji can be viewed as friendly and personable, aligning with a more casual workplace culture. Checking the email flow before sending to a supervisor demonstrates due diligence and professionalism, ensuring that the communication is clear and free from errors.