Cena laughing off all of Roman's big lines was also pretty shitty as well. I thought both performed well tbh, though Cena is obviously a more accomplished promo. I just don't see what Cena laughing the guy off is supposed to achieve unless Reigns really beats the shit out of him.
Not that it is a great reason for Cena to behave the way he did, but I do suspect this is exactly what will happen. If it is Reigns vs Lesnar at Mania, there is nothing to protect in a future rematch, so you might as well give Reigns a decisive win to get him on his way to his Mania showdown and Cena is Cena. When he comes back from the movies, it isn't like he'd be damaged goods or anything like that. At least that is what I hope happens after last night.