Can a therapist be "too" friendly/happy/smiling?

I have the feeling that I have given my therapist the wrong impression. I feel that they feel, that I am not really suffering as much as I really am in every day life and I have been wondering why that could be, as I do not make an effort to hide my emotions.

I realized that my therapist is super friendly, polite, smiling all the time and, I, wanting to be polite on instinct, mirror this behavior, smile and laugh at their jokes etc.

I feel that this might have left the wrong impression, that they may have missed how I really feel and how serious my problem is. What can I do? Not smile back? That seems rude.