Day 1 asked "What if?"

For me, Day 2 asked "Why?"

I love that day 2 has us dive right in to the 2 most important character aspects you need to think about: flaws and motivations. Both are key components to an interesting story. Without flaws, nobody is going to like or care about your character. Without motivation, your characters are just going to sit there and twiddle their thumbs.

Nobody wanders into conflict just to entertain the reader. They need a reason to jump in over their heads (and quite frankly, if Mr. No-Flaws had jumped in over his head, I'm not sure I'd care enough to look for a lifeguard...)

The protagonist isn't the only one that needs motivation. I'll argue the antagonist needs even stronger motivation.

For more thoughts on motivation: https://www.emwelsh.com/blog/character-motivation

And now... Day 3!

The beginning. I love imagining my protagonist's comfortable little world. It may not be perfect, but humans create their own "normal" and we get comfortable in it. Katniss in Hunger Games was hardly comfortable in the normal sense of the word, but she had her familiar routines and things and people. Think Harry Potter in his little cupboard under the stairs or Jon Snow living with his family, despite being seen as an unwanted illegitimate son by most. These are not necessarily happy beginnings, but they are still comfortable.

And then <insert evil cackle emoticon here> we get to completely mess it up for them. That's the fun part.