It's something that I really struggled with for a long time. So much so, that it took years for me to do it in earnest and still weirdly feel bad in the process. That said I've also experienced the growth that comes from it and new, healthier life that sprouts after pruning a plant or a tree. I had to realize that cutting back was actually fostering growth. Even though those branches still appeared to have some life left in them, they were sucking nutrients from the healthier parts of the tree and once removed, the stronger branches flourished and new branches sprouted.
One particular tree I have to trim often is a short, little palm we have in the back yard. This one is a deceptive monster. It looks so pretty with its branches fanning out, weeping towards the ground and offering shade and protection beneath. A thing of beauty until you go to trim it back. Then you discover the devil thorns lurking underneath. It only takes a few encounters with these to realize you need to be very careful when tending to it, or your hands will look like a war zone before you're finished. They hurt, big time and sting with every puncture.