The Best Man wants to look the best, too! It's right there in the name.
A Best Man went off in a groomsmen group chat when he found out that the groom will be the only guy wearing a suit jacket. The groom wants to stand out, but the Best Man is worried that his own look will be "incomplete." The chat was shared to the subreddit Wedding Shaming with the headline "Anyone ever heard of a Best Man-zilla?"
The Best Man did not LOL. He was rather PO'd. The groom explained that to him, a "complete look" meant color coordination, so it would be a "disaster" to have everyone try to find their own jacket that matched.