That's right!
I was on Opera from around Version 3 and it used to be perfect, a simple web browser for displaying web pages. Not only that, it was about a 1MB download. Then they began to "improve" it and I could go on all day about the useless gimmicks that were added but I never used. In fact, the only "improvements" that were of any use to me were the Rewind button (which takes you back to the first page you entered a site on with a single click) and the Mouse Gestures. I have installed the Mouse Gestures in Firefox by means of an extension (the only extension I have installed) but I still miss the Rewind button as it was very useful, so I hope someone can come up with Rewind for Firefox.
What finished me with Opera was when I downloaded the beta of Version 9 and found rubbish such as "Widgets" had been added. I was already thinking of changing once I reached Version 8, as I was finding it was taking for ever and a day to open when I had just switched on the computer. Not only that, but I was forever having to back up my email folder as Opera's built-in M3 mail client kept losing my mail.
Firefox (without extensions) is like Opera used to be - opens quickly, simple interface and quick to use, so I don't think I'll be going back in a hurry.