You'll find the Discworld very much a familiar place if you live in this world. It becomes significantly less fantasy and more satirical observation in the later books. The earlier books in the series lack refinement as he's still testing the themes and so I'd recommend starting with one of the standalone novels.... .Small Gods is probably the best place to start - it'll introduce you to Pratchett's tone and themes without getting you too bogged down in the complexity of the world.

Wyrd Sisters is an excellent introduction to three main witch characters and particularly enjoyable if you like Shakespearean themes. Moving Pictures is a good novel to introduce Rincewind and Guards Guards is a good way to introduce Sam Vimes and the City Watch (though the later Watch books are much better). It's a big world he created and you'll find the characters that resonate with you if you give Pratchett a chance to construct the universe around you. :o)