Gintama is a classic that I have yet to see and from what you write I'm missing out on a lot of things, not just a specific genre. It's always good that the stories are not empty, there are many out there and well I see that this is not the case.
Thanks for the recommendation and reminding me that this exists.
Greetings!
Just as I recommended for musicandreview, I recommend you start with the movie, it's a great jumping off point that contains almost the entire context of the first and second sections of the anime/manga.