Mission critical or just plain critical?

I've really come to dislike the term mission-critical. The sad thing is, I use it all the time. The problem is, developers are hard-pressed to not use the term when referring to important application components. Is there an alternative? Not if you are speaking in terms of marketing. The "mission-critical RDBMS" sounds much more marketable than "really important RDBMS".

Another problem with the term is its' overuse. I might as well have called my first Python program "mission_critical_hello_world.py".