Is misery caused by thinking?

I came across something this afternoon which might be worth a few minutes' thought. 

It begins with an observation by French writer Joseph Joubert (1754-1824):  "Misery is almost always the result of thinking".

My modern source then suggests that to find out whether this statement is true, we should try this experiment the next time we are unhappy:  "Disentangle your thoughts from the situation.  Then look at the situation without the thoughts (or realize that the entire problematic situation was never real, such as when you worry).  When you face the simple 'isness' of the present moment (it's all there ever is), misery has nothing to hang on to any more" 

What do you think?   It seems to me that there is something in the author's suggestion. But also that it is rather simplistic. We are not simply thinking beings. We are feeling, social, goal-seeking, symbolic beings too.