I'd always had a difficult time with adjustment layers. I'd watch tutorials on using them and the teachers would spend so much time on working with the layer, that I never captured how to create an adjustment layer. I decided they were 'difficult' and I worked around them. I knew that someday, I was gong to have to learn to use and create them, but that was always for later, not now.
CS5 has made creating an adjustment layer so simple that I decided it was now later, and time for me to learn adjustment layers. I pulled out my reference book and started reading where I'd left off.
One of the problems I always had was that I'd create an adjustment layer, then try to make a selection. It can be done, but it's much easier to make a selection and then add an adjustment layer. This would be one of the reasons that I like Matt Kloskowski as an instructor. He spells things out in simple sentences, or he demonstrates things clearly.
Why did I decide to really learn adjustment layers? Because Dave Cross was demonstrating something that he called 'simple' and it involved many layers, groups, smart objects, and filters. I've watched the video in several sections, breaking down the steps and it is far from simple. I'm sure it will be possible for me to understand what he's doing eventually, but I've got to understand each of the steps before I can put them together.