Like a few here no doubt maybe take your own lunch/food box to work so Mustard it's a love or like it option but what with ? Beef a bit of salt,maybe Ham off the bone ?
Cheddar Cheese of course, a strong cheddar in a nice fresh white bread with plenty of butter, amount of mustard depends on the spice and exact way you like it. It’s also nice with Cheese on Toast but if anything is going to go on cheese on toast it has to be Worcester sauce, although I am of the opinion that a good cheese on toast only requires salt and black pepper.