Being grounded is all about having control over your own energy and having the ability to choose how much of it you wish to share. More importantly, being grounded gives you the ability to lessen your sensitivity to the energy around you, be it people or even electronics.
The root chakra keeps you grounded. When you are grounded you are able to formulate cohesive thoughts and do not risk being scattered or having your head stuck up in the clouds. Grounded energy also leads to better sleep patterns and reduces the likelihood of experiencing symptoms of anxiety and depression. When you are grounded, you are in control of your own energy, and have the ability to block energy that does not belong to you. It is harder to push the buttons of a grounded person and get a reaction out of them, because you cannot manipulate energy that you do not have access to.
Here is a non-exhaustive list of symptoms you may feel if your root chakra is blocked:
I bring my energy back into my body. I do not entertain that which does not belong to me. I am grounded.