I guess my attitude would be best described as apathy. Apathy is result of the complexity of the system, and the fact the specs and implementations are always in flux, there is no "right answer" how something should be done. Only the fact it works matters. Therefore I try to use techniques and APIs that seem to work the same on all browsers as much as possible.
I use chrome to develop websites because of its built-in development tools, then once ready check it on the major browsers like Firefox $LATEST_VERSION and IE8 (if I know customer still uses XP) or just IE9. The fact Opera has no JS and HTML rendering implementation of its own means I can leave Opera out of my routine altogether, which is what I am pleased about.
I do not care one bit if things are not exactly laid out as I intended. This is not the sort of thing that matters. The site just has to be usable and controls laid out approximately where I intended them to be placed originally. If something isn't quite where I intended but the site is usable, I'll just state that it's a browser issue that likely fixes itself in some future update.
The layout issues that are too severe to be ignorable, I circumvent with IE8/IE9 targeted conditional comments and Firefox-specific CSS workarounds. Most of the time I only need some simple hacks for IE8, as all the other browsers (including Opera) tend to render everything pretty much the same way.