Well as the title says,i read a thread the other day here by @Twohandsondeck about how coffee can stiff the joints to some degree,and iv been dealing with some left knee stifness/pain and i wanted to give it a shot,at the same time i quited coffee i was alredy doing some knees over toes guy exercices like tibia raises, sledge drag and so on,so i cant say 100% that quitting coffee made me fix this, now i have zero issues whatsoever, i will try to reintroduce coffee to see if that was really the origin of my stiffness.