Finding the right mountain bike tyres starts with knowing where you ride. Road tyres are different from slicks and off-road tyres. Mountain bike tyres have to balance both cushion and grip for the surface.
Off-road riders need the kind of tyres that can grip even the roughest surface, while street riders need tyres that reduce rolling resistance on smooth surfaces. Slicks are great if it does not rain. Ride your bike; exercise is good for you.