How would a large character use stealth?

Being that a large creature is larger than most things on the battlefield (and even in normal circumstances), how can one reasonably say that they were unable to see it? Even if it moves quietly, its sheer size should give away its presence (not to mention “a giant shadow is suddenly cast over you” would be a dead give away!

So, how could a large creature reasonably sneak about without being seen or heard, without breaking “suspension of disbelief?”

(note, I’m excluding things like the spell Invisibility)