In a large bowl, combine the ground beef, Worcestershire sauce, garlic powder, onion powder, salt, and pepper. Mix well and form into 4 equal patties.
Heat a grill or skillet over medium-high heat. Cook the patties for about 5-7 minutes on each side, or until they reach your desired doneness. During the last minute of cooking, top each patty with grated cheddar cheese and cover to melt.
To assemble, spread mayonnaise and Dijon mustard on the bottom half of each bun. Place the cooked patty on top, add slices of avocado, pickles, and mixed greens. Top with the other half of the bun and serve immediately.