1. The Government couldn't enforce laws because there was no national Judicial system.
2. The Congress was always short of money because the states could refuse to give some to them. They didn't have enough money to fund an army because none of the colonies agreed to pay their taxes. So they only made them pay for running their government.
3. The States would print their own money and use it instead of the money the congress printed. That caused a messed up system because each state wouldn't accept another states money because no one could decide what the states were worth.
4. There wasn't a very strong Army because of the articles. Because states could refuse to give money and or troops. Spain quickly took advantage of that situation. They closed up the New Orleans port meanwhile Britain refused to move from the Ohio Valley.
5. The states couldn't handle arguments among themselves because there was no President to help resolve issues.
6. They fought over boundaries and river boundaries. They complained about a lot of things.