Old French les riens que j'aime 'the things which I like'. They seem to have gone from positive to negative on account of the formation of the negative in French

I think a better translation would be, "the inconsequential things that I like". They are using the word "rien" not as a positive, but to describe something that is trivial but liked anyway.

In Québec, "c'est un petit rien" (it's a little nothing) is a commonly used expression when talking about something you give that is appreciated but that is not worth a lot of money.

A "petit rien" always brings a smile to your face - especially if happens to be a chocolate éclair. HA!