Time index 0h03m50s: When Lester Burnham (Kevin Spacey) is leaving home and his wife is telling him off about delay, his suitcase opens up and all the contents fall on the ground. Well, few seconds before this happens, you can clearly see that Kevin Spacey is keeping the suitcase closed with his fingers and then, when he release his grip the suitcase opens.

Another detail I want you to notice isn't a slip-up but it could be an error. You have to activate the subtitles on the DVD first. Time index 0h03m24s: Jane (Tora Birch) is in her room using her computer. It's getting late and her mother hurries her up using the car hooter, you can easily hear it in the background, but the subtitles say "Computer beeps".