In a world full of broadband connections, it can be tempting to let your page weight to creep up a bit. While a bit more heft in a page is probably acceptable, it still is silly to write wasteful HTML. Wasteful HTML needlessly increasing bandwidth bills, increases load times, and can (depending on how it is done) increase the browser render times.
One of the things I noticed on a project that I am currently working on, is that the HTML generated dynamically is about three times as large (measured in KB) as it needs to be, primarily due to whitespace. It is not the kind of whitespace that HTML writers put in to make things easy like indentation. It is just wasteful whitespace. For example, in one generated table, for every table cell, there are about 40 lines with 30 – 50 spaces per line between the tags. On this particular page, just removing the uselessly generated whitespace would reduce the page weight by 50%. On the same page, there are tables with alternating row colors. Instead of defining two cell classes in an external style sheet which gets downloaded once as cached, and using the right class in the tag, the HTML writers used an inline style attribute on every row tag. Wasteful!