1) An expression of shock, disbelief, disgust, or just annoyance.
2) A sarcastic response when you really dont care but want to pretend you do.
1) Hey today I had to have my colon removed - (response) GEESE!
1a) Turn the mic off and get off my show guys!!!!! GEESE!!!!
2) Today me and my girlfriend had the greatest day ever - (not giving a fuck response) geese