I think it really comes down to respect and self-awareness, knowledge, and a commitment to practice LNT ethics and minimize your impact on an area as much as reasonably possible. The wilderness purist in me treasures the tranquility that can result from solitude in places where few to no others are around and I've found that the further up longer trails you go, when possible, and the further away you get from roads and what not, the easier it can be to obtain some measure of solitude in such places. Of course, that part of me regrets how many places have exploded with visitors since the wider adoption of various forms of social media among much of the population out there now. But then I must also keep in mind that there are many places I've had the privilege of visiting that I likely would not have come to discover or get familiar with had it not been from someone else's picture(s), video, trip report, etc that was shared online.
Then there is the other part of me that applauds others for getting outdoors too and I have to concede that it can be nice to share, learn of, and discover new places alike with friends and extended social media circles, especially here on BCP with other like-minded members. So with that all said, I really don't mind sharing a trail, a peak, a lake, or other parts of a wilderness so long as all those people in that same space are kind, courteous, respectful, aren't too loud, and most importantly, strive to practice LNT and treasure the natural beauty of the land. Unfortunately, not all who wander into these beautiful places have proactively sought out to understand LNT principles or care to leave it as they found it. Others just plain don't care, even if they do know better, and will go about doing things however they want, even leaving their TP and other trash behind. These are the people I don't understand and wish would stay in the cities and keep their trash to their own places of residence, etc. Seriously...what is so hard about packing out what you pack in. What is so hard about taking up a couple extra ziplock bags to place used TP into and dispose of back at home or wherever the next trash receptor lies? What is so hard about packing out an empty water bottle or beer can or granola bar wrapper or whatever else it may be? What is so hard about packing out a little doggie doo-doo bag? People who leave those bags on the trail for others to pick up are among the worst. Why even go through the effort to bag it up in the first place if you're just going to leave the bag? It'd be better for the environment to just kick the dog's mess off the side of the trail where it can decompose rather than bagging it and just leaving the bag there...
When it comes to human

, I've seen in some high use areas where many people have made the attempt of hiding their excrement and tp by just placing a large stone on it rather than properly burying it or packing it out...ultimately just smashing it all out to the edges and creating both a health hazard and a foul smelling area for others that will inevitably wander through.
I see so many other fellow hikers on some facebook groups I'm in that are always posting pics of all the trash they're collecting and bagging up on trails they hike and I whole heartedly applaud that. And I can only hope that by them posting pictures of all the trash they're finding, that it creates more awareness and get people to think twice about how they're managing their trash when out on the trails and so on. But another part of me questions if those of us who clean up others trash from the trails are just enabling those who don't bother to pack out their trash. I wonder how many out there willingly leave trash behind with the thought along the lines of, "Oh...somebody else will pick this up and pack it out anyway so I won't bother to do it myself..." Maybe others, especially more urban folk, are ignorant enough to assume that the FS and other such agencies have staff hired to routinely pick up the trash along the trails...kind of like events staff and volunteers hired to pick up trash in stadiums, arenas, theaters and other such venues after sporting events, movies, and other gatherings. Still, even if there were...even in those places, I carry out my own trash to the nearest trash can I pass on the way out. It's just common sense and common decency to pack and carry out your own trash and leave a place as pristine as you can for the sake of the environment and for those that seek to visit after you. I think there's a lot of people who probably take the attitude of, "oh..they're public lands, so that makes it partly my land, so I can do whatever I want on it..." rather than the more appropriate attiude of, "oh...these are public lands, so that means they are there to be shared and enjoyed by the public and so I should practice good ethics and not seek to leave my mark on it, vandalize it, or leave any trash behind."
Anyways...I've added more than I thought I would to this rant. Of course, I think we're all just preaching to the choir here. I've yet to actually spot someone actively leaving trash behind on a trail, but when I ever do, I hope I have the nerve to go up, pick it up, hand it out to them, and tell them, "Excuse me, but you forgot this." They'll either be embarrassed and look dumb and go along with packing it out, or they'll give a dirty look at which point, it'll take everything in me to remain polite and try to express how much I would appreciate it if they'd pack out all that they packed in.