Wet wood is common when considering the PT stuff. Although not as easy to find, but there is such a thing as KDAT wood (kiln dried after treatment).
You should consider the project and for things that will be exposed to the weather or high humidity, wet wood is OK, just heavy to work with. Two years of drying would only be required if you are building fine furniture, and hopefully you're not using Pressure treated stuff for that.
In building construction, there are times when you want to minimize the shrinkage (primarily in board width) so there are not excessive gaps. My personal experience is that a 2x6 may shrink 3/16" to 1/4" in width, leaving a considerable gap once dried.
If the project under consideration will suffer with that kind of gap, store the wood for a couple of months on a level surface using "stickers" to allow air flow. I have weighted and clamped stacks of wood in attempt to keep the warping to a minimum.