What GUI features did you dislike at first but use all the time now?

Virtual Desktops.

I thought I could easily do everything in one. Four is good for me now. One dedicated to remote work and three for a rotating band of creative ventures, administrative business, and time wasting.

The key was the ability to set up one space, leave it like that, then do something else and come back to the complex setup the way I like it.

Also I tried tiling window managers, but after a while I came to appreciate regular old floating windows. They're fine and versatile and I'm not anchored to someone else's way of thinking about how windows should flow.

Maybe off topic, and please excuse the hate, but I despise this fashion of hiding the scroll bar on the right and making it as thin as possible.

1) I often miss what isn't there. And I can't be the only one. This means that I literally miss my aim when I'm trying to get to the bar. What should be painless and easy is a pain and frustrating.

2) We have enough screen real estate. It's cheap. Burn that bar in. Don't be shy. Let go of the dynamic fru-fru garbage. Embrace the mechanical. Back in 640x480 land people had burned in scroll bars and did their work and play. Sheesh.

Honestly, I can't think of any. The features that I use and value are ones that I saw the usefulness of when I first saw them. The ones that irritate me are also the ones I disliked when I first saw them.

I wouldn't even bother to write this comment except that your question made me reflect on this and I was surprised by what I saw.

1. Gmail automatically classifying emails into 4 Tabs

2. Google shortcut tiles on launch.

I resisted tabs on IE7 for years, preferring to keep dozens of individual windows open. Now I have dozens of tabs. One of these days I'll start making more use of tab folders :)

I still hate the new Gnome