Popular music lyrics don't often use the word "increment" so I was pleased to hear British Sea Power use it on their first album. In fact they use quite a few unusual words and phrases. But "increment" has stuck in my head because it's such an important word to me.
Take programming for instance. Joel Spolsky calls development "The Game of Inches", but personally I prefer to think of it as a game of millimetres. It's probably partly due to my metric background but also inches suggests you might spot you've made progress after a day, whereas often I'll only recognise some progress has been made on a development project after weeks or months. Perhaps I'm just a slower programmer...
The fact is you can't make a lot of headway in a day. Which is probably why agile development has become popular. I'm not sure about parts of agile development but the idea of taking baby steps to get to where you want to be seems like a pretty damn good idea and I've done it myself for years.
Big designs have lots of problems. It's impossible to keep the details of a massive project in your head. Then things change part way through, or the design wasn't as well thought out as you initially thought. Then your boss tells you we need to release something next week... So it goes on.
The Random Pub Finder started as a craply designed site with hardly any content. Six years later, after hundreds of tiny steps, I'm now quite proud of it.
The FreeFlow Administrator started as a simple project to solve a particular problem I had. A year or so later and it's a fully fledged application that beats the Metastorm provided tools in pretty much every respect.
The commonality between these two projects is that both started small and have had working functionality from the start and at all the intermediate steps. Perhaps it's agile but I prefer to think of it as incremental. Agile brings to mind scrum meetings and pair programming. Perhaps they help but they aren't the important bit as far as I'm concerned.
Which makes me wonder why you'd want to develop stuff any other way. Most projects I've seen with huge design documents actually fall into an incremental development lifecycle as they progress anyway, so why not start out that way?