Current Thanos is not sadistic.
Thanos of old is very sadistic though.
However, Mider, you're probably right.
Thanos has a history of inferiority complex, much suffering, and deep down inside he did love his mother. He killed her by accident, his missile was meant for Eros and Mentor, not his mother.
Also, in Thanos Quest, when he killed the Gardener, he sort of felt bad. He didnt want to fight him at first.
Joker is pure evil. Thanos has changed and is not as evil as characters beleive he is. He's bad but not as sadistic as Joker come to think of it.
I take what i sed before back.