I found a big difference from those doing RT as primary vs guys like me as adjuvant/salvage.
There were a lot of older guys - say 65-80 - doing primary, and not one complained of anything near the side effects I had. I do believe that many of mine are because it was on top of surgery, previous colo-rectal surgeries, and many years with the 'roids and a spastic colon.
Those of us doing adjuvant / salvage to the last one had a lot more issues, if the water-cooler chat can be believed.
I got used to the routine, and had actually gotten to the car to head out on the day after my last one before I realized it was finished. The whole staff at my clinic were so friendly and courteous that it wasn't an issue, once I got the water timing down. It was a break from my work day.