There are many ways to communicate a feeling, and in Wayfair's 'I Can't Explain It' commercial, the characters seem predisposed to showing their emotions with one particular method. In the ad, the various characters talk about the great deals on furniture and home decor available at Wayfair, all while dancing the moves of people who clearly don't have any formal training.
Throughout first half of the commercial, the characters' dancing goes unmentioned. They stick to talking about the prices at Wayfair. The audience can probably infer the reason for the grooviness, but one of the characters makes it clear when he says, "It makes me wanna... I can't explain it" while busting a move. It's so tough to explain how the great the deals are that dancing is really the only way to do it.