I prefer scrolling pages by hitting space.
It works flawlessly, until following happens :

On pages like youtube, where there are buttons such as "load more comments", "load more videos", etc. if
i use the follow command on such a button, the button naturally dissapears, and more comments/videos load
on the page. But now when i hit space to scroll down, i get the following error :

call interacrively: TypeError: elem is null

To fix this i must switch to next buffer (buffer-next), and than switch back to the youtube page, and
then it works all right.

It is strange that this bug does not happen always. Sometimes space works when button dissapears, and
sometimes it does not.