When Fiona is sitting down to drink champagne with Gilbert, the champagne glasses are delivered and Fiona picks hers up. When the shot changes, the second glass disappears entirely from the table without anyone having picked it up.
Michael hits Trevor at the boathouse on the left side of Trevor's face. Immediately after, at Michael's loft, Trevor is putting an ice pack on the right side of his face.
When Michael wants to covertly convey a message to Sam (who is following him), he writes a brief note, crumples it, then obviously drops it to the ground so that Sam will come by and read it. When he does this, the note lands on a dirt and gravel patch of ground. But when Sam drives over to get the note, it is in a grassy patch.
When Sam and Michael walk away from the smoothie cart, there is a woman in a white halter dress on roller blades that pass by them in the background, but seconds later, she is further behind them, and then again after a few more seconds she is much farther behind them.
After the Fionsa blows up the criminals' hideout, Michael uses his right hand and punches his client on the left side of his face. Back in Michael's apartment, he hands his client something from the freezer to put on his black eye, and he puts it on his right eye.
When Michael looks at the crossword puzzle, it is clear that only the first few entries are real words. The rest are letters spelling gibberish. However, this may be intentional, as Michael "decodes" the puzzle to learn when and where to meet his contact. It is unlikely that a correctly filled-out puzzle would just happen to fit his decoding procedure to reveal the correct information.
In the opening scene, nut shells are casually dropped out of a car window into the gutter. While Michael is asleep in the adjacent seat, Fiona is in the other seat with binoculars in her left hand using the 'opposite' hand to casually eat the nuts, no-where near the window. Then she throws shells out of the window which wouldn't casually fall into the gutter.