All in the mind!
Seriously, I've learned that subjective experiences are incredibly unreliable, whether it be the efficacy of a headache tablet you've just taken, or the way my Jag was quieter after I'd valeted the interior (like your car is).
I've even found this on my Enfield. I've been experimenting with running it open and closed loop, and to that effect I've installed a slider switch in the wiring loom in the left hand side box to disconnect the O2 sensor from the ECU. I was of the view that the bike ran just fine - probably a bit better - when open loop.
I'd just had a nice run with the bike open-loop, so I opened the side panel and moved the switch over to the closed loop position. Rode off and the difference was immediate. The idle was less stable, and the throttle response was poorer throughout the range. Only after a couple of miles did I see that the MIL light was still on.
I pulled over, open the side panel and realised what had happened. The metal tab that locks the side panel had caught the switch when I locked it last time and pushed it back to the open loop position.
In other words, all my observations about the way the bike ran were complete bollocks. It's incredibly hard to avoid the placebo effect, and indeed some disciplines rely on it: things like homoeopathy, reflexology, etc. Scientifically and medically they are drivel, but thanks to the placebo effect they "cure" people.
My experiences with the Enfield are what made me develop the "black box flight recorder" I've been working on, so I've got hard, objective data to work with.