At first glance, this is a fairly innocuous situation. But when you dissect it well beyond reasoning, you have a power struggle that has ended friendships, divided families. and started wars.
It’s all about the subtext. If you offer a friend a hug and they offer you a handshake, they are saying that the two of you aren’t as good friends as you thought you were. It’s awkward for both parties, because one of you is all “We’re BFFs!” and the other is all “Let’s keep this professional.”
Research shows that 79% of the time the handshaker will acquiesce and will be enveloped in a hug. This doesn’t just restore the balance; it moves the power over to the hugger. At that point the hugger is all “I’m comfortable with my manhood to the point that I hug my friends” and the handshaker is all “I should have just gone for the hug, and now my right hand is pinned between our chests.”
I would offer a solution, a standard for all dudes to use, but guys are stubborn, and I don’t think any of us are changing. My best suggestion is that both parties meet halfway and do a handshake hug. It’s professional and intimate at the same time, and both dudes walk away feeling manly. Because that’s the most important result of all.