Experience

“The best sorting algorithm is quick sort.”
“Indexes make DB faster.”
“Data should be sorted using ORDER BY.”
“Composition - good; inheritance - not good.”
“Windows is an operating system.”
“You must have transactions in your DB.”
“Java is slow.”
“Don’t eat yellow snow.”
“You shall not self-sign your certificates.”
“Interrupt in Java is broken.”

The IT world is full of mantras/revealed truth, passed (often in oral tradition) among developer tribes. Mindlessly repeated from generation to generation, they cause a reckless usage. At best this results in more harm than good, in the worst case: a total disaster worth whole train of money. The context is indispensable part of each mantra. Right context can help to distinguish proper usage from incoming disaster.