Used to express complete surprise or disgust when something happens or is said!
Ohshi my goodness it stinks in here.
Ben wants to kiss you.
Ohshi my goodness he's fucking ugly!
Ohshi my goodness exams are today
Brandi comes walking in with some pickled peppers
Phew, look at you woman. MY GOODNESS
When you are feeling wittily surprised at an unexpected piece of information!
"OH MY GOODNESS ME! I HAVE TO VISIT THE LOO! I ATE BAKED BEANS *SAYS CUTELY*"