Taxes are basically everybodys money. Collected to finance things that everybody in the state needs.
Roads are one example. Normal people need roads to go to work/school. Factories need roads to transport their stuff. Markets need roads to transport their stuff. And for their customers to get there. So everybody's gotta throw some money into the big pot. And the government uses that to build and maintain the roads.
You should complain if tax money is wasted for unneccessary things. Because it's basically your money, administered by the government you voted for.
so the government has a way of making money to pay for things like health care, schooling, policing etc.. usually taxes go up when the government is running low on budget
so the government has money to protect you from attacks it has an army etc...