Here's A Riddle

[Godbody]

So this man works in a building thats 20 stories high. He walks in & takes the elevator to the 12th floor. He then gets out & takes the staircase for the rest of the way up, to the 20th floor, which is where he works. When work is over, he takes the elevator from the 20th floor down to the lobby. So why doesn't he take the elevator from the lobby up to the 20th floor?

[Godbody]

So this man works in a building thats 20 stories high. He walks in & takes the elevator to the 12th floor. He then gets out & takes the staircase for the rest of the way up, to the 20th floor, which is where he works. When work is over, he takes the elevator from the 20th floor down to the lobby. So why doesn't he take the elevator from the lobby up to the 20th floor?