I've never really warmed up to the thead and tbody tags as you can just leave them out of a table.

<table>
   <thead>
      <tr>
         <th>Foo</th>
         <th>Bar</th>
         <th>Baz</th>
         <th>Qux</th>
      </tr>
   </thead>
   <tbody>
      <tr>
         <td>13</td>
         <td>42</td>
         <td>69</td>
         <td>86</td>
      </tr>
   </tbody>
</table>

 
 

Why not just break into tr tags right inside of the table tag? I guess the extra tags allow for extra things to latch onto in the name of CSS styling and this suggests there is also a tfoot which to my surprise comes sequentially between thead and tbody in the markup. It will still show up at the bottom of the table however. td tags go in a tr tag in a tfoot and not th tags. Bootstrap uses thead and tbody so if you hate these tags like me you've gotta reconsider.