A methodology's weight is a product of its size and ceremony.
Simple rules guide innovative, intelligent responses. Comprehensive rules guide rote, routine responses.
If you have unskilled people who work poorly together, no amount of process will save your projects.
Process is not a substitute for skill.
The best way to get a project done faster is to start sooner
Peel back the facade of rigorous methodology projects and ask why the project was successful, and the answer is people.