Similarly, the OP mentions heroin use as an example of wireheading but this seems to be a misleading example since most people use and abuse heroin in order to get a good feeling.

I don't quite see how it's a misleading example. They notice something that feels good, associate it with utility, and then keep using it, despite the fact that its only utility is the pleasure they derive from it, and they are sacrificing other utility-values in the process for a total net negative utility.