What to do with tough roast

I say grind it up in food processor and make a ravioli filling with some herbs, cheese, etc.

finely dice and turn it into a nice chili or cottage pie.

Cooking a roast longer won't tenderize it unless it's an undercooked chuck roast or something similar. I like Pat's idea. You could also chop it up and use it in tacos.

If it's beef, I like to dice it and make roast beef hash with potatoes, onions and bell pepper.

Slice it up (thin) and put it in the crockpot with ALL the juices. Add thick onion and pepper slices shortly before serving (so they stay a little crispy) and serve on a big french roll. Add cheese right at the end if you want. Favorite use of leftover roast.