You need more of your income to pay for the necessities of life when you're poor, and I think that the income tax system should reflect that. I believe that, in a year, you shouldn't have to pay any tax on personal income up to, say, $10,000. Then I believe the tax should be applied gradually:
5% on the portion of your income from $10,000 - $20,000
10% on the portion of your income from $20,000 - $30,000
15% on the portion of your income from $30,000 - $40,000
20% on the portion of your income from $40,000 - $50,000
30% on the portion of your income from $50,000 - $60,000
40% on the portion of your income from $60,000 - $75,000
45% on the portion of your income from above $75,000, or 40% of your total income, whichever is lower.
For the purpose of this example, I'm comparing total taxes paid, provincial, federal, municipal, etc. That strikes me as a fair system, and a fair rate of pay.
Currently, however, we have three tax brackets, and they apply to your total income. Thus, when you earn over $X, your taxes jump considerably, and they can be bumped there by such things as overtime payments, additional contract work, or whathaveyou. And I can think of few stronger disincentives to earn more income than such a clumsy system.
...James