He's probably just got an upset stomach, but head wants to make out he's shitting through the flareboards and is forced to eat a crap dinner on his own when really it's probably because they had no plans and he feels awkward. Thing is, you can do absolutely nothing on your birthday, at Christmas, New Year or Easter, there's no rules, but because he likes to make a huge song and dance over everything, he finds himself coming unstuck and has to lie in order to keep up the charade. My god, imagine living like that?