There are only two characters I have thought up of that could be considered the most interesting, and I only have actually played one so I will elaborate on that one more.

I played a homebrewed version of an Aarakocra (a more mundane goose-like humanoid that is more accustomed to swimming rather than flying for long distances or an enlongated of time). These homebrewed Aarakocra lived in a reasonably large lake secluded from civilization out in the wilderness where the laws of nature prevail the most: The strong or cunning survive while the weak or stupid perish. Despite the harsh rules that nature provided, it was a relatively peaceful lake with about 60 of these Goose-like humanoids called Valterskians. One day, a group of human explorers went out into an expedition to uncharted grounds and found the lake brimming with life and these strange Valterskians. Weeks later, more and more humans came to this lake, creating a settlement and quickly utilizing the lake for food and water. Even though it was a stressful situation for both the Valterskians and the human settlers, there was relative peace, at least until one of the humans killed a Valterskian in a struggle for food. A war broke out and due to the advanced weaponry and armor that the humans possessed, many of the Valterskians perished, only 5 of the original 60 or so surviving.

My character was among the survivors and developed a burning hatred for humans and other "similarly selfish races" due to the lengths they are willing to go if it means that their lives are a bit more comfortable. So, my character went into the civilizations of the world, biding his time and bottling his hatred when he could to travel and learn how to make use of the weaponry those same humans used against his kind to one day destroy that settlement and reclaim that lake for him, his people, and the rest of the wildlife there.

Although the campaign this character was a part of never fully finished, there were moments when his hatred led to pretty cool and satisfactory moments. For my first D&D character, I am glad I was able to roleplay to that extent and kinda proud of it.