Why did the Egyptian people oust the new President Mohamed Morsi shortly after they ousted the old President Mubarak?

There is no "silver bullet" type answer to this. It can be answered in many different ways by many different people. But I believe that the majority view is that the Egyptian people who took part in the Arab Spring that ousted their long time leader President Mubarak did so because they felt he was leading an oppressive regime that didn't represent the people in the Country. Therefore they decided to overthrow their current Government and wished to establish a Democracy of the people with basic human rights and social change. But when they democratically elected President Morsi they felt, after his 1st year, that he was doing the very things they were afraid he might due if he won the election. Which was to appoint a lot of Muslim Brotherhood allies to key positions as well as moving toward an Islamic state under Sharia Law or under a oppressive religiously lead regime cording to the opposition of Morsi. So instead of going through another election process, they chose to use the Egyptian Military to overthrow Morsi immediately and install a citizen government until they could put together another democratic voting process.