"Laundry Day" is, quite possibly, the most adorable song ever. Dancing in the laundromat = extreme squeeing on the part of this troper at the sheer cuteness of it all. Damn you, Joss, for ensuring that it will never be a reality!
For me, it's when Billy brings Penny a frozen yogurt and pretends it was accidentally given to him. "What a crazy, random happenstance!" Awwwwww.
Even though it's mixed with a little sadness, in the middle of So They Say we see that even though Billy isn't at the laundromat because he's busy plotting evilly, Penny has brought a frozen yogurt for him.
Penny's part of My Eyes / On the Rise. While Billy's part is dark ("I cannot believe my eyes, how the world is filled with filth and lies."), hers is uplifting and hopeful ("And you believe there's good in everybody's heart, keep it safe and sound. With hope you can do you part, to turn a life around.")