That Part Is Too Small For You - Johnny Sneed

When actor Johnny Sneed (Parks and Rec, Painkiller, Trumbo, Fever Pitch) got the advice to turn down a role in a blockbuster because "the part was too small for him" he agreed. He was too big to do something so small. Years later, he still regrets turning down that role. Why does this stand out as the worst advice he's ever got?