To not suit someone

I don't like driving, and driving itself isn't my cup of tea, but unfortunately nowadays cars are a need

Non mi piace guidare e guidare non è il mio pane, ma purtroppo oggigiorno l'automobile è un male necessario

Politics is not my thing and therefore understanding Italian politics is absolutely out of the question

La politica non fa per me e capire la politica italiana, poi, è assolutamente fuori questione

Nick loves swimming and snorkeling, but he doesn't scuba dive. Diving is not his thing because he's afraid of deep waters

Nick adora nuotare e fare snorkeling, ma le immersioni non fanno per lui perché ha paura della profondità

This phrase is definitely British in origin. The positive version was used from the late 19th century; the negative is slightly newer, from the 1920s