In a large bowl, combine the softened cream cheese and mayonnaise. Mix until well combined.
Stir in the shredded cheddar cheese and finely diced pimento until evenly distributed.
Add the onion powder and garlic powder to the mixture. Season with salt, black pepper, and optional red pepper flakes or cayenne pepper. Mix until thoroughly incorporated.
Transfer the pimento cheese to an airtight container and refrigerate for at least 1 hour before serving.
Serve as a topping for crackers, filling for sandwiches, or dip with fresh vegetables.