This study was released last week that claims "when people are emotional, some switch from the preferred right-side hug to the left, a phenomenon that can be explained by a quirk of our brains: they’re not symmetrical."
So basically we do different hugs for different situations.
Personally? I think a hug is like a handshake. The same hug for my mom is the same hug for a friend/acquaintance.
The worst hug? The "bro hug" and the "shug" (shake & hug).
Which side to you hug on?