Boo

Dill thought Boo didn't want to come out because perhaps he had nowhere to run to. Jem reached the conclusion that Boo wanted to stay inside because ' folks in the world ' were too mean to each other. Outside his gothic cocoon was a world made up of people who were so busy being people that they forgot they were human beings.

Jem was correct. In his own right, so was Dill. Where would one go when one had nowhere to run to? More importantly, why would one want to run if one was even remotely aware of the existence of a world full of hyenas out there - watching, waiting, still and silent now, mad with laughter now.
Boo came out - of his prison or haven, that depends on the perspective you endorse, if you will - when he was required. He saved lives, in fact his benign existence isn't completely useless before he decides- or is forced into deciding- to save lives. He awarded Jem and Scout with little treasures for their 'interest' in him or perhaps because he saw something of his childhood in their antics, or most likely he caught glimpses of a childhood he painfully acknowledged he never had.

I think Boo would've liked to know how Scout felt about him eventually. She doesn't say it as definitively as Jem or Dill, so I know I'd like to know.
Yep, I think Boo would've liked it an awful lot.