A friend of mine who is a therapist says that decades in practice have convinced him that people's greatest weaknesses are really their strengths pushed too far. A very generous person may end up giving away too much. A supremely honest person may alienate people with too much truth. Someone who is extremely understanding may end up getting taken advantage of. You get the picture.
It makes sense that even good qualities or good intentions need to be moderated with a healthy sense of realism and practicality. That's as true in politics as it is in life, for politics is the art of the possible. Don't get me wrong - politics needs idealism, and many great leaders started their political careers with their heads firmly in the clouds before the gritty reality of compromise and deal-making dawned on them.
An old schoolteacher of mine used to love to quote the phrase that if you're not a communist at the age of 20, you haven't got a heart - but if you're still a communist at the age of 30, you haven't got a brain. It's crude and simplistic, but points to the truth that to make a difference in politics, one must be willing to change.
It strikes me that many younger people, for all their much-touted open-mindedness, fail to grasp the reality that those who achieve most in politics are those who can master the art of the deal.
Some of the most vocal opponents of the programme for government within Fianna Fáil, Fine Gael and the Green Party are younger members. Both Young Fine Gael and the Young Greens are outright opposed to the deal.
Ógra Fianna Fáil issued a terse statement to say it respected the views of members. Hardly a ringing endorsement. It all smacks of a form of political puritanism that could render the real business of running the country impossible. Irish voters have long since abandoned the idea of one-party government. Coalitions - despite the ups and downs - are here to stay.
Politicians on all sides need to understand that compromise is not the same as selling out one's principles. No one gets absolutely everything they want in a negotiation, but so long as it doesn't betray their principles should settle for a reasonable win for the common good. Ask any couple who have been married for a long time, they will tell you that the secret of their success is being willing to compromise because they agree on the shared project of making a life together.
No relationship is perfect, of course, and no political marriage is made in heaven either. One former minister told me once that he endured each Cabinet meeting with what he described as a weak smile and a strong stomach. And yet, in doing that, he believes that he was able to implement the lion's share of his party's policy. You know, what the voters elected him to do?
Former Tánaiste and Progressive Democrat leader Mary Harney is credited with reassuring a jittery John Gormley of the Green Party at the height of the financial crisis that the worst day in government is better than the best day in opposition. It would be easy to dismiss this as a cynical approach to power, but anyone who has served in opposition for many years will tell you of the frustration at not really being in a position to do anything about the things they care about.
Political neophytes may find it difficult to accept the fact that none of the three parties working to form a government together received a mandate to implement all of their policies. Sinn Féin didn't either, and despite what Mary Lou McDonald claims about her agenda for change, fewer than one in four voters backed it.
The Green Party's former deputy leader, Mary White, this week urged younger members of her party to "temper idealism with pragmatism" and allow the party to enter government. She was met with a predictable holier-than-thou response from those who seem content to sit on their hands for another five years rather than try to make a difference in the teeth of a dreadful financial crisis.
Some Greens are arguing that their negotiators didn't get enough in the programme for government talks, despite the fact that any objective commentator will see the process as a huge win for Eamon Ryan and his colleagues.
If anything, it will be Fianna Fáil and Fine Gael who will have to take the heat from many voters who will be adversely affected by things like carbon taxes and policies in relation to agriculture.
What makes the puritanism of some members of the Green Party all the more remarkable is the fact that they campaigned during the recent general election on the mantra that we really only had a decade if we wanted to halt the worse effects of climate change.
If they really believed that, why were they content to sit out half of that period and watch the people they say can't make an impact fail? Surely if they are serious about climate change, making a compromise to have an impact is more important than being able to say 'I told you so' at the next election.
Politics should be about making a difference, not ranting from the opposition benches about what one would do given half the chance - and then rejecting that chance. The Green Party has been given an opportunity far out of proportion to its actual support or number of seats. They now have the opportunity to make a difference.