I bought a new car and I'm going to drive it to my girlfriend's poor sister's house.
Do you think your girlfriend's sister want's to see your new car?
Yes, it was really expensive and I can't wait to show it off to her. I'm sure she'll be envious of me.
Its normal to be excited about purchasing a new car, but you shouldn't use your new vehicle to put others down. They'll feel like you're looking down on them for being financially worse off and will get angry. Try being considerate of others that have a worse lot in life.
It's not my fault that she's poor and can't afford a nice car.
I know you're proud of your new car but try to be sensitive to your girlfriend's sister's financial situation. Try to be humble about the purchase and don't make her feel bad that she can't afford a nice car like yours.