No situation is ever made better by yelling “Geez.” Just saying the word instantly robs you of any gravitas or illusion of having the upper hand.
Here, I’ll prove it. Picture Liam Neeson saying the following.
“I can tell you I don't have money... but what I do have are a very particular set of skills. Skills I have acquired over a very long career. Skills that make me a nightmare for people like you. I mean, geez!”
I think the problem is that everyone knows that “Geez” is the midway point between saying “Gee,” and shouting “Jesus!” Saying “geez” tells the listener that you really want to curse, but you can’t quite bring yourself to do it, and if you can’t bring yourself to say something drastic, what are the odds that you can bring yourself to do something drastic?
Of course, I could be wrong. Geez may have some deep meaning. For all I know, when you yell “Geez” you could be calling out to Saint Geez, the patron saint of ineffectual anger.