Why is it a potential problem if a president and congress have different agendas?

If the president and congress have different agendas it will be a potential problem because they wont be able to agree on bills. Congress also has to confirm and support the president’s nominees for the Supreme Court and his Executive office so this could become an issue if both parties don't come to a compromise.

A building, because there are buildings taller than a T rex. Therefore  T rex is puny to the building.