When Grace goes to pick Jimmy up from the bar he has an empty glass sitting across the table from him. But when he reaches for it, it's about half full. Then when he takes a drink there is only a tiny bit left in the glass. After he finishes it, Grace takes it and puts it back across the table. When Jimmy reaches for it again, it's sitting right in front of him, and now half full.
Wade claims to have serviced an Abrams tank in Vietnam, but the Abrams was not delivered to the US Army until 1980 - several years after the end of the Vietnam conflict.