One time I realized I left my sunglasses on a flight (DTW-EWR). Luckily I realized it 2 minutes after I have deplaned. I immediately turned around and went back to the gate, talked to a GA there (the plane was still deplaning at the time). She told me that after we wait until everyone have gotten off the plane, she would allow me to go back and get it. The pilots were shocked to see a passenger trying to get back on the plane, but I told them that I left my sunglasses on seat 11A and they let me on the plane by myself to retrieve it