Olórin learned to cry with Nienna but no one knows where Tom learned to laugh.
Gandalf is just one wizard-maia - even though the greatest of them by any means - but what is Tom? No one knows where did he come from or how long has be been around?
Gandalf is weak enough to be afraid of the master-ring but Tom just toys with it.
Do I need say more?
++ Tom Bombadill
Even if silly, he's the coolest guy in the whole ME. He carries something of Aristotle's
megalopsykhia with him, the highest virtue - to be enough for himself not to count his worth on the opinions of others, and secure enough to be able to hold his ground (or those he cared / were good) if challenged.
One should not step on the toes of a wizard... but even less should one make Tom angry.

(Tom just sang the Barrow-Wight away... Gandalf would have needed threats, magic + fire and brimstone to that effect!)
To be honest I do love Gandalf as all of you others but we need some competition here - and
Aganzir painted my boots yellow anyway!