Why are MPs different?

Yesterday Dr Grumble sat on a committee that advises the government. Clearly he can say no more about the detail. The committee has a few doctors on it but not many. Dr Grumble is the only one that a patient would consider to be a real doctor. The others don't really look after patients. Not directly anyway. Some of those who sit on the committee, in their day jobs, would not be paid that well. One is a teacher. We can claim our expenses and we can claim our time for reading the papers. Dr Grumble under claims. The civil servant in charge of the claims tells him that most of the committee members clearly under claim for their time. It worries her. If we under claim, the budget for next year will be cut. Hospital doctors are well known for under claiming. They used to be anyway. Their thinking was that any money that they claimed was then not available to patient care. The way things are going with private businesses ripping off the NHS it is no wonder that such attitudes are changing. But it is clear, nevertheless, that many of the other committee members who are not doctors do not feel that it is right to take all of what they are entitled to from the taxpayer. So why do MPs take a different line?