It's a truism because it's true. But Tim Yeo has taken it to new extremes. He has ended his political career in failure twice.
You might remember his name from being one of the Conservative Ministers with tangled private lives who seemed to crop up in the papers so much at about the time of Back to Basics campaign. That was the end of his ministerial career.
But then a glorious second life opened up for him as Chair of the Energy and Climate Select Committee, a responsible position which he combined with some outside interests "yielding a total income of just under £200,000 a year, for some 560 hours' work". Not too bad eh?
All until he decided to sue The Sunday Times for libel (for suggesting that he was willing to accept money to push for new laws, act as a parliamentary advocate and matters of that kind). The judge, it seems, did not consider him to be all that honest:
"I am quite unable to accept this evidence. ... Experience suggests that in general those who are not interested in money tend not to get much. I can think of none who convincingly claim to have no interest in money, yet end up with an annual income in excess of £200,000. I do not consider that Mr Yeo is such a person. In my judgment this evidence was untrue. I am not persuaded that it was honest either. ... He also resorted on occasion, when under pressure, to answers involving bluster not only in their content but also in his manner. ... This was no kind of answer to the question, and Mr Yeo cannot have believed that it was. He took on an air of exasperation if not anger, which struck me as created or at least exaggerated for effect. This in my view was a deliberate use of a hot-tempered counter-attack as a diversionary tactic. Overall, I did not find that Mr Yeo presented convincingly. ... His evidence about [one point] has been false and, in my judgment, dishonest. ... When a fish wriggles on a hook, it goes deeper into the mouth and guarantees that the fish will not escape. So with Mr Yeo's evidence on this issue. His twists and turns in the attempts to escape the obvious served only to emphasise the problem that the 22 May email presented for him."
And so his second career ends in that, and a bill for £411,000 as an interim payment towards the defendants' costs, plus his own costs and more costs to come. Oh dear.