Read Night Watch while drinking a large glass of Shut the Fuck Up.
Pratchett's work started out as funny, nerdy shit that didn't have anything to it other than funny, nerdy shit. He freely admits his work in Color of Magic and Light Fantastic isn't as good as his modern stuff; what's fascinating about his books is you can see him grow as an author with every new novel.
Night Watch is the best of his books. Read it and then try and say he's some one-note nerdlinger jokester.