I remember taking over a website around 2007 that was built completely with tables. I was having a bit of a layout issue, and found many missing </td> and </tr>

I remember taking over a website around 2007 that was built completely with tables. I was having a bit of a layout issue, and found many missing </td> and </tr> tags throughout the code. A ha! I'll go and fix everything and validate the HTML. The entire layout was built upon those missing tags, and once added in, everything fell apart much worse than before I had gone in and "fixed" everything.