Thinking about how Charlie had thought of Mac as his best friend ever since Dennis banged the Waitress in season one, if not his entire life, only for Mac to say it's bullshit. The entire time Charlie had thought of Mac as his best friend, Mac has thought of Dennis as his. Surely, this wasn't always the case. Mac had been friends with Charlie far longer than he has been friends with Dennis. For most of their lives, Mac must have thought of Charlie as his best friend. When was it along the way that Mac's idea of who his best friend was shifted? When did he decide Charlie no longer fit the bill? What if I started throwing up and screaming and punching the floor?