To believe my feelings or my eyes?

To Mandai Road, 43 km. I got a shiny new toy yesterday, made by an original equipment manufacturer (OEM). Being excited, I adjust my toy without reading instructions. A piece falls out, taking my heart along with it. It takes a while to put it back together, then install it on my bicycle. I take it for a test ride today: my first ride of 2007. The Q-factor doesn't feel right. But to the naked eye, it looks OK compared to the old component. What should I believe: my feelings or my eyes? Time will tell - when I test my new toy on a multi-day ride. Maybe I should've bought peace of mind by buying a branded (instead of OEM) version. But who knows if the former (which costs more and heavier) would cause me grief, or would I feel it's better since it costs more and is branded?