Not every country allows monetary loans to be structured in a manner that allows the lender of the money to charge interest over the period of the loan, although this structure is very typical for western nations. For instance, the typical arrangement of an automobile loan, allows the buyer to purchase a car by coming to a financial agreement over a set period of time, in which the amount of money that will be paid in total by the borrower to actually become the legal owner of the vehicle will be greater than the amount of the loan, of which that difference of added money is the interest so charge by the lender. While this is a very common procedure, in fact, the norm as well as being the backbone of the banking institutions as we know them in today's western nations, that is not the case in most Islamic countries, that see usury, or even the very loaning of money at what would be considered a reasonable rate of return for the lender as not being permissible.
Further to the point, the Islamic religion is not an outlier, as Judaism through its Torah has historically condemned usury, except for the notable exception of the lending of money to non-Jews; additionally Catholicism also for hundreds of years, until this modern banking age, has condemned usury, and even Hinduism and Buddhism has historically condemned usury. Of course, modern day money lenders don't consider banking as constructed in today's world to be usurious, but merely, a fair and voluntary exchange of the access of capital or money for a reasonable interest rate, of which, for those with very good to excellent credit, this may actually be considered a fair viewpoint. However, money lenders, also loan money to those that have poor, fair, and good credit, at interest rates that often are extremely high for auto loans, credit card loans, and subprime mortgage loans, of which quite deliberately the people that have credit ratings that are far from pristine, are subject to interest rates that are double or even triple the amount paid of someone that has excellent credit.
Clearly, the lending of money or even the access to monetary credit is dependent upon the credit worthiness of the recipient, of which, for the most part, such credit worthiness, is really just another way of segregating the class hierarchy of citizens, so that those of the lower class, who clearly are the ones that can least afford to pay the highest interest rates, as well as those obnoxious banking penalties and fees, are the very ones that do that; whereas those of the highest class, are privy to the lowest and most competitive interest rates, and rather than penalties and fees, typically have a significant portion of that augmented instead with rewards and perks for simply being part of the most privileged class.
This essentially means that those that lend money often structure their model specifically to exploit the unknowledgeable and weak for their own profit and benefit, and far too often find that the easiest parties to exploit are those that have the greatest need but often not the resources, alternatives, or credibility for a truly fair exchange to be consummated. So too, those that make money, simply from the loaning of money, haven't really labored or done anything of substance to earn that additional money; for the true cost of that money so loaned, becomes solely borne by the person or institution that has that money loaned to them, of which far too often, the lender knows for an absolute certainty, that the deal is structured in such a manner, that however the loan turns out, they will profit from it, and the borrower, especially the ones subject to the most usurious rates, will not.