>>Your income is taxed, but then your employer's is also. So his earnings are already trimmed, and the proportion of value that you have created and which goes to you is already trimmed. Then you go buy things which are taxed, but the price already contains the tax the manufacturer (and the wholesaler, retailer, advertiser, designer and all of their lawyers) will have to pay...

Most jurisdictions allow costs to be offset before tax is calculated. For example, if a company pays $100K in salaries, it can deduct that $100K from its income and not pay tax on it. The salary earner pays the tax. Ditto raw products or items purchased for resale: if wholesale price for a tractor is $40K and a dealer sells it for $60K, the dealer does not pay income tax on the whole $60K, only on their surplus after all costs are calculated. Usually they also claim back the sales tax so it's paid only by the end user who often also can claim it back if the goods are used to make other goods that attract tax.

Even at the end of the chain, some jurisdictions allow others' tax to be imputed. E.g. if company tax rate is 30% and your tax rate is 33%, if a company distributes a tax-paid dividend you can impute the tax they paid and only pay the difference- 3%. IOW the eventual tax is your 33% on that income, including what the company already paid. You don't pay 30% via the company and another 33% for your own tax. Interestingly, US corporates pay tax and then their dividends are again taxed as you describe.