What makes somebody tick are the things that cause someone to behave, feel or think in a particular way. When you refer to what makes someone tick you mean the things that cause someone to be excited, make the choices that they do or what motivates someone.

1. Her desire to be the best tennis player in the world is really what makes her tick.
2. The interviewer was looking forward to chatting with the entrepreneur and finding out what makes him tick.

1. Our customer's success is what makes us tick.
2. I can't get excited about the recent developments in our industry. They're not radical enough, they don't really interest me or make me tick.