Well, I would say the money that you are holding is of other people and not yours. Considering tax amount as the govt's/country's share would be a better thing. I think this concept of govt. taking our money forcefully comes from the fact that we just don't want to contribute willingly. If taxes weren't there, then a country's development won't be there. And since people would never willingly do their contributions, force is required. That's just how we contribute....