Always a struggle for me. I saw Canada's demo CF-18 at an airshow a few years back and was having simultaneous thoughts of "so this is why we can't afford clean water for our indigenous communities" and "HOLY SHIT IT SOUNDS SO COOL".

In addition to the reasons other people mention, placebo is a helluva drug. If you believe the name brand is better, it may actually become more effective for you even if the active ingredients are the same as the generic.