You can use
<u></u> for underlined stuff (I don't think there's a markdown equivalent).
Amusingly when I was doing the candle problem in my head before continuing to read I was wondering if the box was strong enough to hold up the candle and if it was okay to destroy the wall with the thumb tacks and then trying to figure out a method of attaching the box to the wall with the candle in it without damaging the wall and then questioning whether it was really absolutely necessary to attach the box with the candle to the wall XD
I don't overthink things at all nope not me
Well, I think I'm starting to understand the money motivation thing a little better now (I can understand the obsession with money seeing as it seems to be needed for everything, otherwise I just find it a real nuisance at best and unnecessary hindrance at worst for that exact reason).