I'm a big fan of Getting Things Done. It lays out a pretty good system for dealing with tasks that need to be done. I find it helps to know the workflow and follow it by habit so that I can quickly burn through my to-do list and not get too stressed about new tasks or requests coming in. It's a pretty good system and it works for me.
There's always exceptions.
Today I set out to do a fairly small task on my list. Probably a 10-15 minute task all-in-all, involving setting up a small informational page on our company intranet. As I got into it, I realized that the page would be way better if it was part of a broader site containing related information, with the page I was setting up one of several sub-pages. It's the kind of organizational thing I really like setting up, and something I honestly thought would make a big difference where I work.
So I just did it.
Or most of it anyway. The point is, I completely waivered from what I was doing and spent about an hour and a half on this new task. The idea and the creativity hit me and I acted on it. If I had strictly followed the GTD system, I would have had to stop and add it to my to-do list, made an outline of what I wanted to do, and then get to work on it. If I'd done that, I would have completely lost that creative drive I was on. I would have had the task or outline sitting there the next day, not be as excited about it anymore, and probably not have done it.
I'm not saying there's not a time and place for that kind of planning and brainstorming, and I'm not even saying that GTD gives you a strict set of rules to follow. My point is that I had a system that worked, but I knew when I neeed to break from it, and came up with some great output as a result.
I've seen quite a few project managers who have their PMP certifications who follow every project exactly according to the methodologies laid out by the Project Management Institute, only to have their projects languish or fail. They spent so much time making sure their project was being done to 'code' that they weren't able to adapt to the project's unique situation or stakeholders. The PMI, like GTD, has some great methodologies, but I think it's important to understand when they need to be used and when they can be forgotten if a proejct is going to have any real success.
In a broader sense, I think this can be a problem with other 'systems'. From ones as small as diets to more important ones like religion, ideology, and even laws. You can follow a diet, but you'll drive yourself crazy if you never have a chocolate bar ever again. There are those who choose to interpret everything in the Bible literally (snake handling, subjugation of women), and those who just follow the important stuff (love, compassion, forgiveness.) Who are the people you'd rather hang out with?