At the moment the gardening career is my favorite. My Sim went to Uni and can work from home now. He's a single dad with a huge garden and lab. He's level 8 botanist. My Sim before this was a floral designer and worked from home also. I love the work at home aspect but not the freelance careers. I don't like rejection and the respective actions of those careers.
I also enjoyed the business career choosing the investor branch. They make a lot of money as an investor.
Lastly, my go to careers before University were Secret Agent and Astronaut careers. I enjoyed both career branches in each. Going to Uni really helps with getting a advanced level high paying career.
I don't care for the active careers because IMO they are very controlled, repetitious and mind numbing to me. I don't want to ask a coworker for a crystal when my Sim already has one in his pocket. It's mindless to me. When I played as a Scientist all I wanted to do is run around a collect things but the game as a different idea. That work space has a lot of collectibles. The lot is only available during work hours and does not allow time to go explore the area which I want to do as a player. This made the career really frustrating to me so I don't play active careers.