It is wrong to skip work.
Joe woke up from a long night of partying and is nursing a hangover, but his boss expects him in today.
Joe wants to feel better.
Despite not feeling his best, Joe eats a healthy breakfast, takes some aspirin and heads into work.
Joe calls in sick to work, so he can stay home and take care of his hangover.
Joe's boss see's that he doesn't feel well, but appreciates him coming in and sees Joe as someone who can be counted on.
Joe comes across as an unreliable worker to his boss.