I’m a big fan of vertical whitespace, and find it strange that more fuss is made of tabs vs spaces (which doesn’t really affect readability) than vertical spacing (which does).

Here’s a simple code example, randomly picked:

$max_width  = intval( get_option( 'thumbnail_size_w' ) );
$max_height = intval( get_option( 'thumbnail_size_h' ) );
// last chance thumbnail size defaults
if ( ! $max_width && ! $max_height ) {
  $max_width  = 128;
  $max_height = 96;
}

Compared to:

$max_width  = intval( get_option( 'thumbnail_size_w' ) );
$max_height = intval( get_option( 'thumbnail_size_h' ) );

// last chance thumbnail size defaults
if ( ! $max_width && ! $max_height ) {
  $max_width  = 128;
  $max_height = 96;
}

That single extra line makes such a difference when scanning code. Imagine trying to read a book with no paragraphs.