Dandelions (Taraxacum) are the bane of the neat gardener. In the spring they grow fast using the energy stored in their tap-roots. Before you know it they will be cheerfully flowering and then quickly producing many wind blown parachute-like seeds. After the snow melt and spring rains the soil is moist enough to easily dig out perennial weeds like dandelions. Use a long trowel or a specific tool called a dandelion weeder or dandelion fork. You could also use a wide old screwdriver to dig down deeply into the earth and remove the whole root that resembles a thin carrot. Any parts that you leave behind are likely to root so the more that you can get out the better. I like to remove dandelions from the beds and borders but I am not so particular about the lawn.
If you like bitter vegetables, the dandelion is edible in salads or cooked. You can also make dandelion tea and dandelion wine. Just make sure that where you are gathering your dandelions is free from any previous herbicide use.
If you are a laissez faire gardener sit back and enjoy the bright yellow flowers that will dot the lawn in a couple of weeks. Just remember to duck when you see your neighbor with the perfect lawn going to his mailbox.