There are things he tried to pass that wasn't good for the people. In response, many Republicans in Congress decided to pass their own Reconstruction policies. Johnson vetoed many of these laws. He vetoed the Freedmen’s Bureau Act and the Civil Rights Act of 1866.
This convinced many in Congress that they no longer wanted to work with the president. If President Johnson tried to veto a bill they passed, the Republicans in Congress usually had enough votes to overturn his veto.