joeboxer,
My thoughts exactly. When I first started to play, I'd pick up a cue from the bar stock and play a few games. Then I'd switch shafts. One night I played great with a certain cue and kept up with that cue for the entire night, some 5 or 6 hours. I had played my best ever games to that date, and it convinced me that I needed to get a cue of my own for the sake of consistency if nothing else.
The cue that started it for me was warped very noticibly, except I didn't notice until after I had a knockout night.