It is very important not to get in the garden too early in the spring when soils are quite wet. If you do, you can cause the soil structure to be destroyed. As an example, think of a garden soil with good texture as being similar to a nicely textured chocolate cake. If you take the chocolate cake and ball it up in your fist, the nice spongy texture is destroyed and you have just a solid lump. Essentially the same thing happens if you work a soil that is too wet. Continuous walking on wet soil or tilling will cause the structure to collapse leaving just a compacted mass.
You can test a soil to see if it is too wet by taking a handful and squeezing it. If water drips out, the soil is obviously much too wet. Even if no water drips out, use a finger or your thumb to push into the soil.If it crumbles and breaks apart it is appropriate to do regular garden activities. However, if it squeezes together and your finger only makes an indentation it is still too wet.
You can also damage the structure of the soil around trees and shrubs if you are pruning them in the spring when the soil is too wet. The continual walking on the soil as you move around the plant compresses all the soil particles together with the result that the air space is completely eliminated. This can be avoided by either waiting until the soil dries out before you prune or by placing several boards on top of the ground so that your weight is evenly dispersed and not concentrated in just the relatively small area of individual foot prints.