Exactly like the English expression: "it's not my cup of tea" (or not), the French have "c'est pas ma tasse de thé".
French is always easy but for us French learners, we've chosen to learn this beautiful language. It's our tasse de thé.
In true great franglais fashion, the French have adopted "mug" and deemed it masculine. You'll never forget "tasse" and "mug" when drinking out of this chaque jour.