I'm not a front end developer - I'll be the first one to tell you that (I'm a chef!). That doesn't mean I don't feel the pain of being a FED, though. In the past, a really tough task for our front end team has been styling Sitecore's Webforms For Marketers. The way these forms work, the HTML that is outputted onto the page is generated during the page load, so all of the style definitions have to be made and put onto the page beforehand. After many hours of tedious CSS tinkering, eventually the form looks the way we want and stays in the right place.