Pilot reported a runway excursion due to an inability to effectively manipulate the rudder pedals while wearing sub optimal footwear.

Narrative

After normal flight and landing; long rollout with aerodynamic braking was used. At low speed; I went to apply brakes; and inadvertently pressed the right rudder pedal to the floor; and did not apply any brake. Was unable to apply any pressure to left pedal. Departed the runway at low speed. I called on my passenger; also a pilot; to apply the brakes from the right seat. He did so; and the plane stopped on the grass with no damage. Probable cause: unfamiliar footwear. I normally fly in sneakers. On this day; due to cold weather; I was wearing hiking boots. On the rollout; I discovered I could not feel the pedals.Factors effecting human performance: I have been struggling with fear in the cockpit for > XX years; since a long flight in IMC in which I encountered prolonged strong downdrafts. I have retrained several times; trying to enjoy flying again. During Covid; I was not flying at all; and in the last month; had made a few flights to try to find peace and happiness in the cockpit again. So; I was nervous; and that probably kept me from being fully aware of the obvious; that these shoes have very large thick soles; that could interfere with manipulation of the pedals.