Inception
This classic movie ending as everyone talking about it even 10 years later! In order to find out if they are dreaming, the characters use an object. For DiCaprio, he uses a topper. If it falls, he's not dreaming. The end scene shows the topper spinning and spinning, but it never falls and the screen cuts out as it wobbles. The director has stated that they are indeed in the real world and that he isn't dreaming. There are other clues to confirm this.