--It overstimulates our system, causing our senses to work overtime on stimuli that aren't necessary or important.
--It draws our attention away from what our focus should be on.
--It makes it more difficult to relax both physically and mentally.
--We are constantly reminded in our brains that we still have a huge to-do list.
--It causes feelings of guilt and embarrassment, particularly when someone drops by unexpected.
--It frustrates us by making it hard to find anything we need.
I don't think you need any more reasons than this. Choose an area in your home and start your decluttering process. Refer to past posts if you're not sure how to begin. Go on, you can do it!
Here are some great pieces about clutter from Psychologytoday.com