If you borrow money, and you agree to pay it back, there should be a good faith effort to do so.
But that is only one type of debt.
In the US, where I live, Apartments are incredibly bad about charging fees after you move out, and give you very little recourse before sending you to collections.
Parking tickets, and red light camera tickets are huge sources of revenue for the city, and Seattle uses them when they need to increase city coffers.
I look at it this way, if they're not going to play by the rules, I won't either.
Also, I don't like paying for stuff.
Unless you take things from people. People are different. Then you should pay for those things by bleeding all over the snow or whatever. (I don't know how money works in your country. In the US we usually just use dollars. There's not much snow right now and having everyone's blood everywhere can lead to public health problems. See also: Ebola.)
Anyway. Thank god there are no people at corporations. And thank god all corporations are the size of Walmart and can easily withstand financial losses due to non-payment.
Well, you should care, because they factor it in by increasing prices for consumers. You're just getting everyone else that shops at Walmart to cover your debt. That's irresponsible, and I see no difference between owing Walmart $10 and owing your friend $10.
This[1] is the type of situation where I believe the victims(yes, I'm using that word) deserve to have their debt removed.
1. http://www.npr.org/2014/09/15/347957729/when-consumer-debts-...
It is really a fabulous book, and can help explain why many people in many cultures feel as you do, who benefits from that belief, but also how debt has never historically been about moral obligations but has always been a contract between two parties, with limitations on both party's obligations.