Hmmmm. I don't think I've played any other games that were DnD. I've played other CRPGs, but I normally just pick an alignment. I've never gone as far as creating my own character with their own backstory. Is it fun? Can you describe your favorite character to me, and how their decisions may differ from your own?
It's hard for me to break them down to a handful of easily digestible sentences, whilst still doing their nuances justice. I tend to blather on and on, and I don't think anyone wants to see a whole novel of me rambling about various characters. Especially with english not being my native language.
But just a small example to answer a little bit of your question:
I've had a cleric, who genuinely wants to do good, and is extremely forgiving, even to people that have wronged her. She also simply improvised on the spot, didn't really care about making big plans, just trusting things to work out. I also had a very paranoid drow druid, that always watched out for traps and always had a plan up her sleeve, if things went sideways.
Those two obviously play very differently, when faced with the same situation.
Take the scene with Nettie:
For the cleric it is easy to forgive Nettie the deception attempt, and the fact that she wanted to poison her. She understands the reasoning, and doesn't find it in herself to be angry about it. She will promise to take the poison in case anything goes wrong.
My druid has the opposite reaction. She expected as much, but she's not going to walk away from that, risking anything to happen. And she definitely is not going to make any promises.
I tend to start pretty basic. Pick a class that I like, then think about what type of character I want to play as. What are their goals? Do they have strong principles or morals? Where would they have grown up? Where they orphans or did they have a family? What was their life like before they got abducted? What are their likes, dislikes? Even just something as mundane as their favorite food.
You don't need to go that much into detail, of course, just do however much you'd like.
I simply tend to add a lot, starting with the raw scaffolding of a character and then adding more and more, until I arrive at the tiny details.
Ultimately its just about using your imagination and your headcanon. I find it very enjoyable to do, and thats why I prefer Tavs, for the additional freedom. It ultimately comes down to personal perferences.
