[Diesel_Dave]

I was wondering whether sometimes mods have a placebo effect. For example, I recently switched to some lower weight synthetic oil, which has resulted in some record-breaking mileage for me. I'm wondering though whether it's really all the oil or not. Could it be that the oil does provide some benefit, but much of the benefit comes from me looking at my mileage display and thinking, "Wow, this is a really good day today, maybe if I really focus, I can break another personal record." So, for example, maybe the oil provides a 5% improvement, and my increased focus provides another 5% (maybe?).

I'm not sure if there's really any way to prove or disprove this. Anyone else thought about potential "placebo effects"?