Spending the morning putting some EQ on several buses. All sounds good. The grand kids come to visit, and I forget to lock the door on my studio. Come back later to find every knob and slider on my Mackie changed and Sonar, just a happy camper, recording all of this, over my previous efforts. It would have been easier to recover if my granddaughter hadn't unplugged every cable she could get her sticky little fingers on. 
I still love my grandchildren, but sometimes it tests my endurance. 

This thread is a barrel of laughs and brings back many "F Sonar" moments when it should of been "F me!!!" 
Aside from all of the above, my one persistent fopa is forgetting to turn down/disable the phantom power on my lovely E100S and next time have it blasting feedback thru my monitors when I've switched from headphones...
 
I usually end my sessions in the weeee hours long after my brain is fried and can't seem to avoid this particular "F'n A" moment...

I am usually plagued with interruptions while I am trying to work on music and often break off in the middle of editing something. When I return I have forgotten exactly what it was I was working on and move on to something else. This inevitably results in various unfinished parts within a project or things that don't quite work as intended. I always end up doing a lot of fixing in the later stages.

Hard to be more stupid like me:
I´m learning some very useful Sonar shortcuts
like ctrl to move all fader aso at once
and find myself
often in moving every fader solo.