Thank you everyone for your answers.

It seems almost everyone says they raid for the challenge. I can understand why.
When I am focused and the boss has 10% or less HP, I can really excited and begin thinking "We can do this!"

But I think my satisfaction from challenge might be somewhere else.
I find a great challenge in gathering all of my own mats and switching specializations to craft all my own gear. And I love completing my achievement logs.

Last night I challenged 3rd floor again. Our group is becoming more stable. We reached final phase many times.
Our new record is 6% remaining HP.

But to be honest, using HQ food and HQ Supramax potions during the fight (especially when we wipe before even reaching final phase), it very disappointing.

At the end, one of members told everyone else to raise the IL before tomorrow. I didn't check the other's IL, but mine is already 254. There is nothing I can do to raise it anymore until next week's scripture reset. I imagine the others must be in a similar situation.

It's a little vexxing to hear it.

I will probably limit myself to just 1 raid set a day, if that.