1) India. Lots of conflicting laws. Lots of conflicting paperwork. And as a foreign company you'll probably pay more in bribes ("voluntary non-disclosed payments to ensure success") than you would in taxes, because the alternative is that they send the police after your local employees and maybe try to have the local court seize your property.
2) EU. The VATOSS is straightforward, but the income tax systems are not. Within the EU, France is the worst, followed by Belgium, Denmark, and Germany. Portugal and Ireland are very chill about tax returns. For the bad countries, there is lots of paperwork. Literally every transaction must be documented. On both sides. And they will ask for the documents when they audit. And they will challenge any cross-border transaction that results in reduced local income.
3) Africa. I've only dealt with South Africa, Nigeria, and Egypt. South Africa was the easiest to deal with, and Nigeria was surprisingly business friendly other than the constant requests for bribes. Egypt should have been straightforward (and there is a bit of language barrier), but the bribes were not optional, even to file basic tax returns.
4) South America. There's a lot of it. So much of it. In Brazil, you need certified letters just to send and receive money...including tax payments. And there's a lot of requests for bribes in other countries. But once you get past the language barrier and the logistical hassle, it's actually quite straightforward and logical. If not for the military dictatorships and drug gangs, South America would be a good place to do business (from a compliance perspective).
5) USA. Lots of laws. Lots of jurisdictions. But all relatively straightforward. It only gets complicated if you choose to minimize your tax burden (or maximize your refund) by taking advantage of the many, many complications. If your only source of income is W2 income, you could finish your tax return in 15 minutes.
6) Canada. Even Quebec, which insists on doing everything in French.
7) Australia. It's the least complicated tax system I've dealt with, and the easiest to work with as a taxpayer. The ATO is also quite easy to reach...I'm almost always able to get a human on the phone within 5 minutes.
