An incomplete list of my mantras (in the sense of guiding principles not mystical formula).

• Be curious, not judgmental.
• Don’t repeat yourself (DRY)
• Everyone you meet is fighting a battle you know nothing about. Be kind. Always.
• Keep it simple, stupid (KISS)
• Make it work, make it right, make it fast.
• No broken windows. (source: The Pragmatic Programmer)
• Premature optimization is the root of all evil (source: Donald E. Knuth)
• You aren’t gonna need it (YAGNI)