Placebo effect...at the gym?

My own placebo experience derives from my level of motivation when I work out at the gym. In certain occasions, when people exercise at the gym, it is common for them to consume an energy drink or supplements (i.e., pre-workout powder mixed with water, gatorade, etc) prior to working out. Consequently, the idea is that with these energy drinks or supplements, you'll have more energy to workout and have an increase in workout performance and efficiency. The concept of the placebo effect comes into play when my friend gave me what I thought was an energy drink mixed with the pre-workout supplements and as a result, I didn't get tired as fast while exercising and felt more motivated to work out while at the gym. As it turns out, there was nothing in the drink that my friend gave me, and so, in this case, the placebo treatment was the drink I had before I worked out, and the reason that my gym performance was enhanced was due to the fact that I believed that it would be if I drank the "pre workout" drink.