Never doubt the bond between lifelong pals Ben Affleck and Matt Damon. But if you do, Affleck will be happy to reassure you, apparently. In honor of National Best Friends' Day on Wednesday, the "Batman v. Superman: Dawn of Justice" star posted an absolutely adorable throwback pic of him celebrating Damon's birthday back in the day. The series depicts Damon receiving his birthday cake and then pushing Affleck's face into it. That's what friends are for, right?