You might refer to your favorite friendly bus driver as a good egg. A good egg is a nice person.
Good egg is a friendly, old-fashioned way to talk about a good guy or a kind person. When you call your next door neighbor a good egg, it's clear that you're fond of her. The expression originally came from its opposite, bad egg, British public school slang from the 1800's for someone who was not nice. Fifty years later, good egg emerged as a casual way to talk about a good chap or a decent fellow.