In a skillet, brown the ground beef over medium heat until cooked through.
Drain excess fat and add taco seasoning to the beef; follow package instructions.
While the beef cooks, make the special sauce by mixing mayonnaise, ketchup, mustard, and vinegar in a bowl.
Warm the flour tortillas in a separate pan or microwave.
Start assembling the tacos by spreading a layer of the special sauce on each tortilla.
Add a generous portion of seasoned beef to each taco.
Top with shredded lettuce, diced tomatoes, and shredded cheese.
Sprinkle diced pickles on top for that classic Big Mac flavor.
Drizzle a little more special sauce on top and serve immediately.