It is expected that you help and support coworkers
One of the clients at James' work suddenly asked for a huge rush job, and James' boss asked everyone to come in on Saturday to help the associated account manager.
James doesn't want to give up his Saturday.
James argues with his boss and says they should bill the clients for some temps to come help out.
James calls in sick on Saturday because he doesn't want to deal with the workload.
The boss agrees, since the client shouldn't have given them so little advance notice.
James' coworkers are irritated with him when he comes into the office on Monday.