How do I get in that blocked door?
I've wondered this ever since I got to 7 island on FR, and Sootopilis City in Ruby.
In both of these games-I don't know about Johto or Sinnoh-theres a house with a door, blocked by either boxes or trees. You can't use an HM move on them, and the resident of the house doesn't help at all. In FR, the lady says something about being a great trainer in her day, and now she just watches present day trainers grow to be great too. I think Sootopilis person says about the same thing.
So my question is, How do I get in that blocked door? And what's behind it?