post some who looks mad or scary all the time

Kageyama Hiroko from Gilgamesh.
(also known as the countess)

She doesnt just look angry all the time, 95% of the time she is.

Kamui (Gintama) This is his scary look, but he's still cute<3

Kurosaki Ichigo from Bleach
he practically always looks like that.

Megatron in the Transformers Unicron Trilogy (specifically Energon and Cybertron) constantly has this angry expression on his face (which kinda fits him when you think about it), mostly due to the... questionable CGI quality not allowing more than one facial expression on the transformers themselves.

Kakuzu from Naruto >.< Don't get me wrong, I love him, but I think if I met him, I'd run and him...

Jin & Mugen - Samurai Champloo
I dont think Jin smiled once in the entire series an Mugen always had a pissed off look on his face