Testing-ever get fed up?

I must admit there are aspects of this hobby that drive me nuts and steer me away from getting caught up in "analytical" listening for any great length of time.
Don't get me wrong I have great admiration for those who can A/B test components and cables to the cows come home but it ain't for me.
My query is how often do you totally confuse yourself doing this?
Do you ever lose faith in some of your audio beliefs due to this?
The background behind this is the following....
Several times in the past I've got mixed up to what I'm actually listening to (sometimes wrong input on an amp or forgotten I've changed something).
Famously one time me and a fellow audio friend were remarking on the subtle changes and deeper bass on a track after certain combination changes in my system with one of his components-only to find we'd listened to the exactly same combination twice.
How we laughed.
At the moment I'm taking notes on running in a SACD player and today I messed about so much with different combinations in my system that by the end of the day what sounded like big differences earlier on,no longer did.
I did stray from my rather "strict" plan on listening and just totally confused myself.
Do too many changes lead to listening fatigue?
Perhaps too from this posting,experienced testers can highlight some do's and don'ts of listening tests.