2. Because it gives you a big awesome bone that - when combined with stock, lentils, thyme, garlic, and a bit of sausage - makes for one of the most amazing meals you will ever eat.
3. Cause what the fuck else are you going to make a vinegar-mint sauce for?
4. Leftovers are amazing in sandwiches built with sourdough bread, bitter greens, Dijon, pickled onions, and more mayonnaise than should be considered healthy.
5. It gives you a reason to consume insane amounts of garlic. Not that you need a reason anyways, but justifications are always nice to keep in your back pocket.
6. Fuck vegetarians.
7. Fuck vegans, too.
8. I'm pretty sure lambs are threatening the ecosystem by eating grass, pooping everywhere, driving SUVs, trolling online political forums, and posting pictures of your children on 4chan just to be total dicks. You're doing your part to keep the earth safe by devouring them and and putting a halt to their evil ways.
9. It pairs well with white and red wine! What other goddamn food can do that?
10. Because you're encouraged to "cook" it by serving it practically rare. If you take it over medium-rare it just becomes leather. Put those freaks who like their meat well-done in their place and give them some education by serving a red-pink slab of lamb.
Bonus Reason. It's so easy to cook. My method is thus...
You will need:
5 cloves of garlic, chopped
a few good sprigs of fresh rosemary, chopped (not dried, you heathen)
many sprigs of fresh thyme, chopped (again, dried just won't do here)
2 tablespoons olive oil, plus extra
many good grinds of freshly cracked black pepper
2 teaspoons of kosher salt
A leg of lamb (bone in, for fuck's sake), 4-5 pounds is more than enough to feed your family and give you leftovers.
Preheat your oven to 325F. Trim the leeks of their dark green tops and the tips of their roots; cut them in half lengthwise. Run them under a bit of water to get the grit out but keep the halves together and neat. Douse them in a bit of olive oil and hit them with some salt. Place them at the bottom of your roasting pan as they will absorb the drippings from the lamb and get softer than your gut and so savory you'll just die.
Now this next part you can do in a food processor, but I like to use a mortar and pestle so there's some texture and, somehow gosh darn it, the flavor it better. Plus, more fun. Place the garlic, rosemary, thyme, olive oil, salt and pepper in whatever you're using to mash them up and mash away into a paste. Smear this paste all over the leg of lamb. Hit the lamb with another good sprinkling of salt and pepper.
Place the lamb on the leeks. Cover with some foil.
Roast for 20 minutes per pound, removing the foil after the first hour. You want the internal temperature to be between 130F and 135F, which is a nice medium-rare. Plenty of pink is key.
(If the lamb doesn't drip that much fat or juice, add a splash of chicken stock or water to help the leeks along. This is rare that I have to do this, but it does happen once in a while.)
Allow the leg of lamb to rest for 15 minute before carving and serving. This is lovely on its own, but some mint sauce, red wine vinegar, or just flake salt are nice accompaniments. With this and the leeks I usually serve just some bread and sheep's milk cheese alongside to keep it in the family.