I am going to have a go at an honest and non-condescending reply to the OP.
A "backstop" is just a fall-back position. It's designed to ensure that there will be no border in Ireland whatever the outcome of future UK-EU trade negotiations.
You need a border where two countries have different rules about the taxes that must be paid on goods that enter their territories, and/or different product and safety standards.
The function of the border is to ensure that taxes get paid and that imported products meet local product and safety standards. It is intended to prevent smuggling (ie, importing banned goods, or importing permitted goods but without paying taxes) and, for example, to prevent consumers from being exposed to unsafe foreign products (like salmonella-infected chicken or contaminated baby milk). It's not possible to do this without some sort of border infrastructure.
There are two reasons why Ireland doesn't want a border. The first is geography - there are hundreds of crossings and there are, for example, Irish villages and farms where the only way in and out is via NI. The second is of course the history of English occupation and the troubles.
The "original" backstop would have kept Northern Ireland in a customs union with the EU while also ensuring that goods that could be sold legally in NI could also be sold legally in Ireland/ the EU - "regulatory alignment".
However this would have led to a border in the Irish sea, which the Unionist politicians (who are popping up the Tory govt) objected to. So the backstop was extended to the whole of the U.K.
People are not having breakdowns over the Norway - Sweden border.
Both Norway and Sweden are in the EEA, which means they apply common standards to goods. This is a far closer relationship than the one that is being proposed between the U.K. and the EU. And even so, there is physical infrastructure at the border.