It sure is. I even found myself turning things the wrong way at times before cutting, even though it was something I did at least once a week.
On walls I like to cope corners, if at all possible. With coped corners angles aren't near as critical. "IF" the crown is to be painted then you have the best of all possibilities. The painter will use caulk on all joints, and then the paint will cover and make things look so good.
Don
Try it now, Don... It's amazing, how difficult it is for me to visualize the proper orientation, at 68... When it was easy, even 10-15 years ago... I always made mistakes, while doing this... But, generally due to distractions... Not due to inability.
Perhaps, Michael is in the right track... Perhaps, I need to do more visualization training, to slow the atrophy of my remaining brain cells... as my arteries continue to harden and my brain cells continue to die.
I have made a few mistakes bending sheet the wrong way.
This never happens on the first bend, made a few patches with difficult angles and f’ed up the final bend.

Of corse these are not the patches shown here on mud.
Of course not!!
Yeah, it always seems to be the final cut (or bend) and generally the easiest... What surprised me yesterday was the 2-3 times I made multiple compound angle cuts, test fitted it and was please... The I cut the other side of the corner and it didn't fit AT ALL... I recut it and it didn't FIT AT ALL... Then, I noticed it didn't fit because the first side of the angle was angled backwards.. E.g. Cut completely opposite to what it should have been... The fact that I didn't notice, during the test fit, was the most concerning... Where was my head?!?
I useta build wooden boats and I wont even try to use a miter without one of these angle finders are best used prophylactically, like a tap and die set.
I've used those and you're correct, they definitely make life easier... Mine is in my furniture maker tools... In a barn, in Central Texas... I brought my chop saw and my table saw and very little else... Truth be told, Dianna said I wouldn't be "building stuff"... and I fell for it... Naive, yes? Plus, we simply don't have room for all those tools here.
This is why I've become the 44 Lead Mechanic... To keep me out of Dianna's way, at home, and ensure I can potentially bail myself out of remote areas... I never had an interest in mechanical stuff before... I loved building stuff for Dianna's shop, in my spare time... But, this is the new old me.