Why does my PS4 controller keep making my player go to the left when I walk?

over long periods of time, dead skin cells and plastic dust from constant analog movement can build up in the little chamber underneath the joystick, the best approach besides buying a new controller would be to open up your controller using a security screwdriver, often reffered to as t7 or t8,9 etc. and use isopropyl alcohol and a qtip to rub off the excess dust and other gunk while avoiding the qtips contact with any other exposed elements also ensure that there is no power going to the remot when you do this. hope that was helpful