I've experienced software installer bliss.
Here's the scenario: I went out and downloaded an application so I could test its compatibility for a dev. I ran the installer, which popped up a UAC dialog. I confirmed the install, and then got an incoming e-mail. I read the e-mail which directed me to a webpage where I filled out a survey. The survey reminded me of a website I needed to read and then write a blog post about. After the blog post I noticed that my build window had finished compiling, so I checked in the code I was working on and started in on some new edits. Not long into this I got another e-mail from the dev, which reminded me that I had never finished installing that application.
Suddenly, I started sifting through the myriad of windows on my desktop looking for the installer that I had neglected. Not there. The installer wasn't even running, says taskmgr. So what happened? On a whim, I checked the Start menu, and there it was. My app, fully installed, ready for me to run, and patiently waiting for me to launch it on my terms.
I was shocked, to say the least. Where was the installer wizard? Where were the six dialog boxes to click through? I got none of that. No intro page telling me that yes, I've launched the installer, and I need to click Next to continue. No pages and pages of EULA text that nobody reads, but rather just clicks Next to continue (The EULA was available at install time, but the installer didn't need to rub it in my face). No installation summary that indicates that it's going to install one component (The Software) and that I need to click Next to continue. No demands that I shut down other apps, or focus-stealing confirmation page after the install.
And finally, no messing with other parts of my system. Where do you want me to put my icons in the start menu? Can I dump icons onto your desktop? How about your quicklaunch bar? Your startup folder? How about your documents folder? Is it okay if I change your browser homepage? Mind if I also install a toolbar, an IM program, and a keylogger while I'm at it? This installer didn't do any of that, nor did it even ask me about it.
It was surreal. Sparse. Minimal. I didn't know how to react at first. All the installer did was install the software. And it didn't even make a big deal of it. The application was just there, ready to start when I needed it, and not before. I guess what surprised me was that it had never even occurred to me that an installer could run without my hand-holding. Years of conditioning by needy installers had desensitized me to all of these unnecessary clicks. Not since the days of XCOPY installs on Win95 have I been able to multi-task while installing software. It's refreshing.
This is what I mean when I talk about software that Just Works.