Those who do it always say it is the worst job in politics.
It is certainly one of the most difficult - the ultimate example of responsibility without power.
But there is one man at Westminster who does not see it that way.
Nigel Fletcher, a former Conservative central office staffer, has made it his life's work to study the noble art of opposition.
While others crowd around power, and attempt to get close to those wielding it, he is ploughing a different furrow.
"It is, I think, an eccentric obsession that I have. But I think Leader of the Opposition should really be seen as an important office of state. More so than it is now," he says.
"Because it has these two aspects to it. One of which, of course, is to be a future prime minister, they hope, but it's also an important position in its own right because you are, essentially, speaking for the minority, or actually, in most cases, the majority, of people in the country who have not backed the incumbent government.
"You are not just, in Ed Miliband's case, the leader of the Labour Party, you are leader of Her Majesty's Opposition. You are leader of all the parties in opposition in Parliament."
What people tend to forget, argues Mr Fletcher, the founder of the Centre for Opposition Studies, is that the Leader of the Opposition plays an important role in Parliamentary scrutiny and democracy.
In his new book, Mr Fletcher, who is also deputy leader of Greenwich Council Conservatives (the opposition group naturally), argues that it is possible to be a great opposition leader even if you never manage to get your hands on the ultimate prize.
Neil, now Lord, Kinnock, honorary president of the Centre for Opposition Studies, makes what Mr Fletcher says is a "very insightful" contribution to the book.
The former Labour leader has, he argues, been "unfairly maligned" because he lost two elections and never made it to Number 10.
"He is very frank about his own shortcomings and about the reasons for his defeat and I think he is probably harsher on himself than he needs to be because he was able to lay the foundations for Labour's victory in 1997.
"You can't get away from the fact that by the time Tony Blair took over many of the fights he picked with the party were fairly superficial because most of the work had been done by Kinnock."
So, as someone who has studied these things, what tips does he have for Ed Miliband, the newest leader of Her Majesty's Opposition?
The first is "have a strategy and stick to it", he says.
"The problem that most Conservative leaders had was that they started to confuse tactics with strategy and chasing media headlines becomes an obsession," he adds.
The second is "have discipline and instil a sense of purpose in the party so it's seen as an effective alternative government".
This is what Neil Kinnock struggled initially to achieve, he argues, but did eventually manage to portray Labour as "a credible alternative government, rather than being a disunited rabble".
Thirdly, and this could be the most to difficult to achieve, don't "oppose for opposition's sake".
A criticism often levelled at opposition parties is that they do not have any policies but Mr Fletcher argues that it is not necessary to "come out with a fully worked out response for every situation".
"It's sometimes difficult to keep that restraint but a party in opposition should be, as Churchill said, a lighthouse not a shop window. In the sense that you should offer a direction and a narrative of what sort of a government it would be without necessarily detailing every dot and comma of what it is going to do. Mainly because the government will steal all the best stuff."
Edward Heath, who was Conservative prime minister for four years in the turbulent early 1970s, should stand as a warning to those who think it is all about policy detail, says Mr Fletcher.
"In a technical sense he was probably the best prepared leader of the opposition of recent times but as soon as he hit government, and the overall strategy failed, all of that was useless".
But however brilliantly they perform at holding the government to account, surely it will all be forgotten the moment the leader of the opposition steps across the threshold at Downing Street?
"I think what's interesting is that those who have become prime minister, by definition, have their period of opposition overlooked. So the ones that stand out as being interesting leaders of the opposition tend to be those who were only leaders of the opposition, such as Neil Kinnock or Michael Howard."
But it must be hard to avoid feeling like a failure, if, like Kinnock and Howard, you go down in history as a leader of the opposition who never made it into power.
"They are certainly very philosophical people. I will say that for them," says Mr Fletcher.
How To Be In Opposition, by Nigel Fletcher, was published on Thursday, 17 February by Biteback.