For some odd, wonderful reason, 2015 saw a major boom in pajamas onesies for adults. This year, it seemed like everyone was rocking the onesie, making it hard to pick just one favorite moment. Just how big was the onesie this year? Well, on the runway, one piece items of clothing like overalls, rompers, and jumpsuits returned to the world of high fashion. A-List, B-List, and C-List celebrities alike showed up to red carpets rocking the fashion jumpsuit, while this was the Summer of the Romper. But when it comes to sleepwear, just as many celebs were rocking the adult…