I find myself having a love/hate relationship with Lua where I work. We have a solid in-house C++ game engine, and like good little agile programmers we exposed a good portion of it directly to Lua so we could prototype and get stuff up and running quickly.

Now it has reached a point where some people are writing their entire game in Lua and it just ends up becoming one impossible to debug mess. This wouldn't be as much of a problem if there were a decent, cross-platform remote debugger available -- but I have yet to find one that doesn't rely on doing silly things like DLL injection (Decoda). I would pay good money, like >= $500 a seat, for something that Just Worked and met the needs I listed above.