The phrase ‘cup of tea’ is used to define something you like, or perhaps something you’re good at doing.
Example in use: “Fiction novels aren’t really my cup of tea. To be frank, I prefer crime thrillers or historical books.”
This phrase was known to be used in a negative way. For example: "He's not my cup of tea". The positive version of the phrase this started in the late 1800s when the British changed the phrase to "my cup of tea” used to describe something they enjoyed.