Finely chop the onion. Seed and finely dice the green pepper.
In a bowl, combine the Worcestershire sauce, mustard, brown sugar, and tomato sauce.
Place a large skillet or dutch oven over medium/high heat. Add olive oil and ground beef. Saute the beef for about 5 minutes until cooked through and no longer pink, breaking it up with a spatula. Season with salt and pepper and add in the diced peppers and onion. Cook another 5 minutes until the veggies are tender and beef is browned.
Add the minced garlic and saute 30 seconds until fragrant, stirring constantly. Add in the sauce and bring to a light boil. Reduce heat to low and simmer uncovered for about 10-15 minutes or until thickened to your liking. Season to taste with salt and pepper and add water if you prefer a looser consistency. Serve on toasted buns for Sloppy Joe Sandwiches.