His facial expressions, with very little movement of body, eyes etc .. it is like Less is More
And to top that I am convinced that Mohnish is one of those few actors who has perfect diction .. in Hindi and Urdu
I am sure some of you will agree that very very few actors (TV artists) pronounce perfectly words like -
Khaas, Halanki, Khana, Khamosh, Gussa, khabar, khayal, etc..