I'm not convinced -- I find the Vista dialogs really confusing for that reason.
First, I read the question, "Do you want to save this file?"
Then I naturally expect "Yes", "No", "Cancel" -- effortless to understand.
If I see "Save this file", "Don't save this file", "Return to application", it takes a lot longer, because I have to parse each button, which is redundant and annoying since I' already parsed the question.
The only time I've found longer button names to be useful are in rare non-intuitive situations, like when copying files into a directory with files of the same name, and there are multiple options you can take.
There shouldn't be a question if it's only going to repeat what your dialog options say -- you don't ask "do you want to save?", you just put up "save file", "exit without saving", or "return to program" without any question at all.
Also, yes/no/cancel are only "effortless" to understand if you read the question first (not everyone does that) and if the question is simple.
An example of doing it wrong: my classroom had an unstable piece of software that would occasionally pop up a long error message that asked "do you wish to continue?" at the end; students wouldn't read the whole thing, but would just click "no", which closed the software.
If the same popup had the error message and then buttons marked "continue" or "close program", it would have been far more straightforward.
Similar issue: dialog boxes which ask a question using words
like cancel, continue, yes, no, or okay, when the question
is followed by buttons using similar or identical words,
but whose meanings are the opposite of the question.
Example from a commercial site:
Are you sure you want to cancel the changes you made?
[ ] OK [ ] Cancel
To clarify, 'OK' is "cancel the changes"
whereas 'cancel' is "cancel the cancel" :-(
If the dialog question were worded as:
Do you want to apply the changes you made?
[ ] OK [ ] Cancel
with the appropriate logic reversal, it would have been clear.
I view sites with issues like this as I would a corporate office
with damaged or out-dated signage - a hint that the products or
services offered inside are unlikely to be any better in quality.
To paraphrase Torvalds, you've been brain damaged by standard Windows button UI.
Mac OS X takes the approach of labeling buttons with action verbs instead. This makes scanning dialogs much simpler; with Yes/No/Cancel, you have to carefully read the dialog message (and hopefully the text is clear) so you make the right choice; or you sometimes make the wrong choice since nearly all dialogs use Yes/No/Cancel and your brain didn't do branch prediction properly.
In your case you are annoyed since perhaps you know exactly what the app is going to do and you don't want the extra 500ms overhead, but for your Average User, clearly defining a button's action is better.
First, I read the question, "Do you want to save this file?"
Then I naturally expect "Yes", "No", "Cancel" -- effortless to understand.
If I see "Save this file", "Don't save this file", "Return to application", it takes a lot longer, because I have to parse each button, which is redundant and annoying since I' already parsed the question.
The only time I've found longer button names to be useful are in rare non-intuitive situations, like when copying files into a directory with files of the same name, and there are multiple options you can take.