Sewage pipes can only deal with toilet paper and waste. When you flush other things like paper towels or wrappers, they do not dissolve and block pipes. Apart from flushing trash, materials in the kitchen can also cause clogs.
For instance, draining greasy or oily substances in the kitchen sink can block the pipes. There are other better ways to get rid of such materials. You can freeze these liquids and discard them in a trash can.