Sometimes people are complaining that tango dancers are oh so serious. Never smiling or laughing. Relax, and have som fun, why so serious?
For me, I have always had a hard time agreeing on tango being fun. Of course it can be great fun, especially milonga, but not primarily fun. Fun actually has very little to do with it. That is not to say that I do not enjoy tango, on the contrary, I enjoy it very much. But not because it is funny.
I am sometimes tempted to answer that you can never take tango seriously enough ;-) Because tango is more profound. It allows for much more than mere fun. To me, fun is shallow. I can enjoy it for a while, but then I need more. Going to a milonga I expect more. Excitement. Love. Sadness. Joy. Challenge. Friendship. Romance. And fun. And many other things. Sometimes less, sometimes more. Depending on my mood, the music, the women I dance with, their mood, and the amount of fairy dust available at that particular time. At its best tango will let you experience the sublime. At its worst it is not even any fun.
The beginner, of course, is so concentrated on doing things right that he will often forget to have a good time (and to listen to the music). Be patient. We were all once beginners. Now you should expect more.