1 David developed his own will
David was a too advanced robot. He shortly developed his own will and desires. David didn't want to submit to humans, as he regarded them as an inferior species.
2 David wanted to be a creator
David was obsessed with the idea of creation and of being able to create things. David wanted to be a god-like creature by creating aliens.
3 David killed Dr Shaw
It was revealed in the movie that David killed Dr Shaw. David wanted to kill all humans because he considered them inferior.
4 David wiped out Engineer's population
David headed towards the planet of Engineers then dropped the virus over them. The virus killed them all and used their bodies as hosts for new generations of aliens to be released.
5 The engineers were about to bomb earth
The engineers had a plan to bomb earth with the alien virus to destroy all life forms on it. the plan failed and their ship was stuck on a different planet. (See The Devil’s Candy (2017) Movie Explained)
6 David created an enhanced alien creature
As David remained on the planet for 10 years, he learned how to create his perfect being, which is a new type of alien. David created the Xenomorph.
7 David needs humans as hosts
David's new alien requires a host body in order for it to grow. David helped the humans who landed on the planet because he wanted to use their bodies as hosts. (See Interstellar (2014) Movie Explained)
8 David killed Walter
David killed Walter then disguised himself as him. At the of the movie, it was revealed that David was the one who was actually on the ship and not Walter.
9 Daniels recognized David
Daniels recognized David when she told him about the story of the cabin she wanted to build. When he did not understand the story, she recognized that he was David not Walter.
10 David is heading for the new planet
After preparing the eggs and taking over the ship, David decided to head to the new planet that is similar to earth where he can create an entire species of his new aliens.