"Courage is being scared but doing it anyway"
I'm not exactly sure where that quote's from but i don't really think it applies to scrum or xp.
John started working at ABC company. He thought he was going to be part of an XP/Scrum team. Many of the questions he asked up front didn't exactly jive with scrum or xp but he thought surely if they say they're doing it, they're doing it.
John got there on his first day and there was no scrum meeting, but he was stuck in HR's office filling out paperwork so maybe he just missed the engineering meeting that's no big deal. He went to IT and got his password and got logged into his machine. A few documents were stacked on his wall-facing desk and he began pouring over some domain definitions and diagrams. This is doing no good, he though, and he asked to be shown how to get into the code repository.
Looking at the code, John became frightfully aware there was no Xp going on here. There were no tests, the code smelled of brittleness and over-complexity with it's lack of interfaces and use of reflection generated code in a multi-tiered mashup of WCF, remoting, and System.Net Sockets.
John just got there, so he thought it was completely innappropriate to begin talking badly about the existing source code and it was also way to early to start griping about the management practices or engineering practices. After stewing about it for a while, he opted to just keep quiet until the scrum meeting, which would surely come on the next day, where he could more tactfully bring up his impediment.
He quietly read his documentation and waited to go home. Upon arriving at day two he was greeted again with a lack of a scrum meeting and everyone went quietly to work on their own little project. Bill was working on service code while Jan and Sidney were pounding away at a demo UI for marketing to show off at the next presentation. Obviously there was no scrum at work here at all, nor does there seem to be an opportunity to express one's feelings about these impediments.
Scrum meetings are the single most important thing i can possibly think of in Scrum. They are the opportunity to reflect on the very recent past, raise awareness to the very near future, and conjure up courage to 'cry' for help.
Test driven design is in my opinion the single most important practice of XP because it enables every engineer to have the courage to change any code through refactoring because he/she KNOWS that this code has a test that is designed for it and every other piece of code has a test that will assert he/she has made a correct change and the system still works.