I also feel better when I use less libraries, even if that may seem irrational sometimes.

I think part of the library craze stems from people who really only want to use the programming language as a tool to get fast results (which is legitimate, of course).

For example in academic contexts you have a lot of scientists who use R with a whole truckload of libraries, often unnecessarily. It reminds me of the plugin craze in the whole wordpress can of worms...