Sometimes we might watch scary movies or read scary books for the thrill of being afraid "just for fun" and it's okay because it's all make believe and we can turn it off or close the book and move on. However, there are some common reasons of why some people might be fearful of decluttering their space.
The fear of letting go of something because you might use it in the future is a common one. Think of a panini maker, an extra screwdriver set, clothes that don't currently fit you, or any impulse purchase you made because it was on sale. Sure, you bought it with good intentions to use them, but if they are crammed in the back of a cabinet/closet or end up living in the basement at the bottom of a box/bag or pile, will you really use ever them or are they just taking up space? To help let items like that go, think that you will pass the usefulness you saw in it originally to someone else who will actually use it. Imagine someone using your donations in their first home or someone staying warm in that sweater that really didn't fill all that well when you bought it.
Another fear could be the fear of forgetting information or memories of cherished people. Old magazines and books hold tons of information, but ask yourself; "In today's age, can I find this information on-line or at the library?" Chances are yes you can, you can even find manuals on-line, so feel comfortable letting all that paper go, because that knowledge is readily available. After someone passes, it's nice to have a few items that remind you of them, but not a household full of those items. Keep a few cherished things, display them and let the rest go. As they say "Keep the best of the best and let go of the rest", because your love for that person will always live in your heart not in the extra set of pots and pans stashed deep in the basement of your home.
Other things that people might be afraid to get rid of are things we feel obligated to keep. Whether it's our children's kindergarten art work, a loved one's belonging or unused gifts you were given; we can feel guilty letting them go. For your kid's art work, take pictures of them, keep a few pieces of their best work if you'd like and toss the rest. You will not be a bad parent if you do that and they most likely wouldn't want them for themselves in the future anyway. If Grandma left you the Hummel collection, or any collection for that matter, that's something she placed a high value on and it may not be your thing. If you like them but don't want to keep them all, keep the one that speaks to you the most, actually display it and then let the rest go....or let all of them go if they hold no emotional value to you. Unused gifts can easily fall into this category too. The gift-giver either liked the item themself or thought you would like it. Once they have given the gift, they have passed ownership of it on to you and it is up to you to decide what to do with it. Keep it and use it, regift it or donated it, the choice is yours. Do not feel obligated to keep something that you don't like or use just because someone else thought you might like it. The beauty is in giving and receiving of a gift, not in the gift itself.
There are many roadblocks that can keep you from letting go of unwanted things. Recognize them and don't be afraid to meet them head on.