What is fair?

I have been reading about the governments plans to stop child benefit for people earning more than about £44K per year and more specifically people's reactions to it. Ignoring the fact that it is a single individual earning more than 44K rather than the joint earnings of a household (although how do you find that out in modern-day marriage-less Britain?) I am interested in people over-using the word "fair". It's not fair, it's not fair!
What is fair? In a totally un-moderated market, I would earn as much as I can. Add in the idea of government and we have to pay taxes. If you pay by a flat percentage, already the system can be accused of being "unfair". If we all benefit more-or-less equally from the government services, why should I pay twice as much as someone who earns half as much money? So OK, let me accept that a percentage is not unreasonable, we then look at various other factors. We have a tax code which gives us £7000ish tax-free each year. This means that the less you earn, the less tax you pay (you pay tax on a lower percentage of your salary) is that fair? Then there are benefits which are paid to various people out of work totalling a large percentage of tax money, why should I have to pay for all the people who don't work? Is that fair? Then we have to gall to raise the tax rate above a certain amount (more than I earn btw!) so that people who are fortunate to earn lots of money have almost half of that taken away to pay for things which other people are using - is that fair? I am single and rarely have any medical help, is it fair that I am paying for a household worth of rubbish collection, schools and elderly care that I don't use while others who earn nothing are getting £1000s of benefits from my taxes?
It seems that "fair" to most people is that if I get more, that's fair but if I get less that isn't fair. "It isn't fair that someone earns a million pounds per year" (although most people wouldn't give their money away if they earned that much!) "It isn't fair that these government proposals hit the poorest the hardest" (despite the poorest already getting a massive load of free benefits.
Here's a newsflash - life isn't fair. I have so little money after paying my bills, I'm worse off than many low-income families despite earning more than the national average wage. The day when someone on benefits has more disposable income than me is pretty sad but I count my blessings and soldier on. I just wish all these "it's not fair" people would shut up and take responsiblity but a state benefit system will never encourage that to happen, only when people have to give in order to receive will they appreciate something and have the self-respect that they have earned it.