Simcha & Breslov

I recently watched a video of Breslov Chassidim stopped in middle of a street in Chevron and dancing with soldiers who were in middle of a break from searching for the kidnapped youths. I was thinking that it is good to raise the spirits of people who might be down. Then another thought crossed my mind, we constantly need to be b'simcha even during mrirus and certainly when performing a mitzvah and certainly when performing such a special mitzvah.