About eight years ago, a ben Torah, whom I admire greatly, mentioned to me that he never says Tachanun. When I asked him why, he candidly responded that it is a very sanctified and “scary” tefilah, and since he has no kavanah, he is afraid of being punished severely. In fact, the Magen Avraham (siman 131 s”k 5) quotes the Zohar HaKadosh who writes that the punishment is very severe for one who does not have kavanah when reciting Tachanun. My guess is that he had learned this Zohar and therefore refrained from ever saying Tachanun. (Note: I am not qualified to pasken halachic questions, though I believe this action was not correct. Anyone who would ever consider this idea must ask his rav.)