Why do Shias beat upon themselves on 9/10 muharram

Re: Why do Shias beat upon themselves on 9/10 muharram

Exactly that’s what Yazeed’s army did when Imam’s head was on spear and his family was crying.

Go on tell us more as to what else you do to celebrate when you see somebody crying at Karbala’s tragedy.

Do you also sometime feel angry at Ahlulbait for saving Islam? just wondering…