Which sphere do you think is most challenging to RP adequately?

Which sphere do you think is most challenging to RP exceptionally?

Assume you're taking a relatively straight-forward approach, and not an interpretation that makes it much easier. E.g, no "I'm sphere Honor but really my character *hates* honor." This isn't meant as a dis against creative takes on spheres.

Here they are, as a reminder:

Earth Air Fire Water
Spirit Para-elements Storms Seasons
Death Fertility Magic Reason
Truth Vivimancy Revelation Music
Healing Protection Creation Mercy
Strength Poetry Deception Necromancy
Concealment Courage Victory Destruction
Rage Combat Order Peace
Chaos War Balance Fate
Honor Dedication Wisdom Knowledge
Purity Greed Justice Judgment
Love Vanity Beauty Passion
Anger Covetousness Envy Gluttony
Lust Pride Sloth Honesty

As an aside, I'd love to see a breakdown of the most/least popular spheres (Probably a bunch of spheres, like covetousness and Para-elements that get basically no takers).

Because there's too much "doing stuff" in CF as it is. It'd be a stretch to even justify walking to the other wide of the world to level up as a sphere-Sloth guy.

I choose covetousness with a lot of characters. It perfectly defines my abilities as a player. I want what you have, but am not good enough to get it. So I'll sit and stew about it and maybe take a potshot or two.

See help Thrakburzug before deciding that covetousness gets no takers.
Almost all of my orcs in the past were covetous critters.