It would be nice if English-like programming languages such as BASIC or AppleScript allowed using but in place of and.
Logically, and and but are the same; only but carries some additional semantics implying contradiction or contrast. (Note how I cleverly avoided using two successive buts there).
Why bother? Well, consider the following example:
If License.IsValid And License.IsBlackListed Then LectureUserAboutPiracy End If
Now read this:
If License.IsValid But License.IsBlackListed Then LectureUserAboutPiracy End If
Although interpreted the same by the computer, the second version makes the programmer's intention more obvious to a reader of the code.
This is similar in spirit to how you can use the in AppleScript and HyperTalk to make code more readable without affecting its behaviour. But this would be even more useful, because complex logical propositions can be quite a pain to decipher when you don't know the original intention. In fact, even constructing them can be difficult when you're having to translate from real-world terms into and and or-terms.