I guess fitting the bike really matters

[FrankR]

I'm making big strides in comfort as I adjust the bike for my body. First was seat cover. Then seat height. Then very important, and I didn't realize this - seat angle.

Today, I reversed the bars. I'm only 5'6" with a short reach, and I always felt like I was putting too much pressure of my body weight against the bars, leaning over.
Reversing the bars shaved several inches off the reach, and the comfort is night and day.

 

[Alaskan]

Adjusting the fore and aft position of the saddle is also very important and can relieve knee discomfort. Ideally with the cranks parallel to the ground, on the forward foot, you want your knee joint to be directly above the axle of your pedal, such that if you drew a line from your knee down through the center of the pedal axle, it would be perpendicular to the ground.

 

[FrankR]

Today, I did - bar height. I believe everything is dialed for me to the max.