No offense, but this is a statement from customers that bothers me the most. The thing is, I DO care. I care a lot about the customer, their experience with our airline, and their well being. Not just their safety, which is of course my first priority, but also that they are comfortable and have a good travel experience.
However, my influence is minute in the grand scheme of things. I have no control over the line at the ticket counter. I do not control the attitude of the ticket agent who takes your checked baggage. I definitely do not control the TSA checkpoint. I do not tell operations to make a gate change between two terminals. I do not tell the gate agent to have a bad attitude and hide in the breakroom until 30 minutes prior to departure. I get the customers after ALL these things... If they have a bad experience prior to this, it makes it just that more difficult for me to ensure they have a good experience with us as a crew. This is why I want to work for a company that offers outstanding customer service BEFORE the airplane is boarded.
You won't find me making "XENA" announcements, but you bet I use light humor to relax the customers. Even as a professional, you can use humor to make things better. I look at it this way: If you were about to go into surgery, would you want a doctor who was stiff and "all business," or someone who used light humor to relax you? I'd want the latter... When I encounter stress, I find humor helps relieve it. You can take it too far, but I think you can take "seriousness" and "business" too far as well.