As an aside, in Islam, people have to pay a 2.5% wealth tax annually for charity.[1]

This does make retiring a tad bit complicated. Say you've saved $3M and are ready to retire. That means each year you're spending $75K just to satisfy this tax.

[1] Depending on how your wealth is structured. Cash is 2.5%, but if you own, say, a business, you pay the tax on the value of the goods, not on the value of the building, hardware, etc. You don't pay Zakat on the house you live on. Agriculture is actually taxed at 10%, etc.