Tab switch behavior
I recently switched over from Chrome and I couldn't figure out how tab switch shortcuts worked when I tried to go forward/backward using the CTRL+Tab/CTRL+Shift+Tab. Turns out tab switching does not work the same way in Opera and that's completely fine. However, I was forced to figure out how to change the behavior to what I considered to be 'normal' and to do that I did a couple searches on Google and the Opera forums which were unfruitful. Eventually figured out how to do it myself by changing key bindings.
I'm not necesarily a power-user but I can figure out solutions to problems and I didn't mind doing all that, but I think maybe a simpler and more convenient setting for this, instead of the hassle I had to go through, can make things easier for switching end-users.
What behavior were you trying to get it to do? If you were trying to make it so that it switches tabs in the tab strip order (instead of recently used order), there is a setting for that:
Opera Menu | Settings | Browser | Uncheck the box for 'Cycle tabs in most recently used Order'.