I don’t think people “feel the need” to litter, it’s just plain apathy, they’re not feeling anything at all. It’s just “I don’t need this thing anymore,” probably more a feeling even, not even a conscious thought, and that’s that. I can’t stand the thought of littering, even leaving my table messy at a restaurant is unthinkable, but some people I know wouldn’t think twice about just dropping trash wherever, even in their own homes. Those kind of people are like animals to me, I just can’t even process what goes through their heads during the day.

It really is a habit thing, I carry my trash in my pocket till I find a bin.

Another thing to note is that, unless you saw someone litter, it's possible the trash WAS in a bin but an animal took it out or the wind carried it away.

I went to toss a wrapper once and a squirrel scared the life out of me

In my city, it’s a lot of drug and alcohol induced apathy.

Yeah, people generally aren't like: I see a bin over there but I think the floor is a better place for my empty wrapper!

It's a combination of laziness, habit and location of garbage bins.

Near me there is a street with a couple fast food restaurants and bubble tea. However the public trash bin at the nearest intersection is at the opposite corner to those shops. Instead there's a newspaper stand that inevitably gets filled with trash every week.

People want to find an appropriate place for their trash but they don't want to carry it around with them for long or bring it back with them.