Basic questions about rotation (from a newbie)

All your info posted previously are very helpful. Yet I’m still getting some behaviors on my BPs during gameplay.
I got this door setting, where the door should rotate to match the motion controller hand. It works, but I can’t explain why, if I rotate the door in the play area, say 90 degrees, then it doesn’t work anymore, it rotates the opposite way, and I also don’t know why.
I had to add this minus 180 on the float in order to get it to work as it has this 180 degrees offset when I tried the first time.


It just doesn’t make any sense to me, on my other tests, if I simply swap start and target input locations, the rotation changes to opposite direction whenever it hits 90 degrees.
Honestly, makes a lot of sense when I’m reading your post but when I try to set this up on my project it just doesn’t work. I tried using set local rotation as well and it gets even worse.
Please help me xD