a lot of that is handled automatically for you in [language of your choice]
Haskell: type checking. Instead of debugging your code, trying to figure out the return types of return data, the strong type checker within the language itself does it.
Perl: type conversion. Instead of having to deal with taking a string of input and turning strings into numbers before doing math on them, Perl does all this behind the scenes for you.
Prolog: inferencing (depth-first tree search). Instead of you having to write an algorithm to explore a tree of assertions to determine the closed-world validity of a statement, you let the built-in inferencing engine do this.
PHP: web readiness. Instead of having to come up with a protocol for embedding Perl into HTML, PHP ships ready for web programming right out of the box. No need to download Perl's HTML::Mason or PLP. No need for HaXML or whatever. Load, lock and rock.
Visual Basic: .NET integration. Instead of having to write win32 libraries and then .NET libraries, Visual Basic comes ready for .NET and win32 programming from the get-go.
Emacs Lisp: IDE integration. Instead of having to use a separate tool for the edit/test part of the programming cycle, Emacs Lisp _is_ the edit/test as well a development program. Thus, you can use one tool for all aspects of development. Additionally, the base GUI for user interaction is the editor, which saves you have from having to write the basic UI widgets.
Shell: shell access. No need for foreign syntax to access shell commands (true of Tcl also). Very easy access to directory listings, etc.