Favourite sandwich?

My favourite sandwich has gotta be mayo chicken in a bagel with crunchy lettuce, satisfying in both taste and the crunchy texture of chopped iceberg lettuce from the shops.

Another one would be sausage and egg with some cheeky brown sauce (British lemmy users know what I mean)

What is YOUR favourite sandwich? Fillings or sauces to go with it, maybe your favourite type of bread?