Perhaps it is an assumption but I would suppose that Hashem would prefer us to serve him through simcha rather than through trepidation. There is certainly a virtue in ahavas Hashem over yirah. Ahava ...
As pointed out here, and noted in the comments, there is no Taḥanun recited the entire month of Nisan. According to MB 429:2(7) it's because of Kedushah. I was wondering if someone can weigh in on ...