Portuguese Words That No Longer Confuse

These two don't confuse me anymore, but in the beginning I was definitely wowing a lot of inappropriate situations:

Oba: Means wow! golly! or amazing! Usually exclaimed when you are impressed or surprised by something.
Opa: Means whoops! or oops! Usually exclaimed when you drop something, bump into someone turing a corner, or ram your grocery cart into another shopper's ankles, in which case it would be quickly followed by a well-timed desculpe [not that this happens very often].

They are clear in my mind now and I use both rather liberally, although being fairly similar one to the other, it is easy to imagine that there could be some level of cross-utilisation in early learning days. I actually learned oba and opa close to five years ago but didn't start using them until moving here, at which point I spent quite some time fumbling one over the other and would often find myself saying whoops when a friend would unexpectedly show up and wow or golly after dropping my papers all over the floor. Smooth....