Understand the system: Read the manual, read everything in depth, know the fundamentals, know the road map, understand your tools, and look up the details.
Make it fail: Do it again, start at the beginning, stimulate the failure, don’t simulate the failure, find the uncontrolled condition that makes it intermittent, record everything and find the signature of intermittent bugs, don’t trust statistics too much, know that “that” can happen, and never throw away a debugging tool. Quit thinking and look (get data first, don’t just do complicated repairs based on guessing): See the failure, see the details, build instrumentation in, add instrumentation on, don’t be afraid to dive in, watch out for Heisenberg, and guess only to focus the search. Divide and conquer: Narrow the search with successive approximation, get the range, determine which side of the bug you’re on, use easy-to-spot test patterns, start with the bad, fix the bugs you know about, and fix the noise first. Change one thing at a time: Isolate the key factor, grab the brass bar with both hands (understand what’s wrong before fixing), change one test at a time, compare it with a good one, and determine what you changed since the last time it worked. Keep an audit trail: Write down what you did in what order and what happened as a result, understand that any detail could be the important one, correlate events, understand that audit trails for design are also good for testing, and write it down! Check the plug: Question your assumptions, start at the beginning, and test the tool. Get a fresh view: Ask for fresh insights (just explaining the problem to a mannequin may help!), tap expertise, listen to the voice of experience, know that help is all around you, don’t be proud, report symptoms (not theories), and realize that you don’t have to be sure. If you didn’t fix it, it ain’t fixed: Check that it’s really fixed, check that it’s really your fix that fixed it, know that it never just goes away by itself, fix the cause, and fix the process. — David J. Agans

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“No human thing is of serious importance”
— Plato

Yesterday, a friend in California, when giving me directions, told me I could take the trail toward the tall pines or turn left and find a field of poppies, growing gold and savage at the edge of the valley.

When I asked which to choose, she simply shrugged and said: either way, it’s all heaven.

— Joy Sullivan, Instructions for Traveling West: Poems

Hazardous attitudes are attitudes that negatively affect the quality of your decisions. Recognizing them is the first step in neutralizing them. There are 5 attitudes:

• Anti-authority: Those who do not like anyone telling them what to do.
• Impulsivity: Those who feel the need to do something, anything, immediately.
• Invulnerability: Those who believe that accidents happen to others.
• Macho: Those who are trying to prove that they are better than anyone else. “Watch this!
• Resignation: Those who do not see themselves making a difference.

Here’s a list of antidotes to the 5 hazardous attitudes discussed in the previous chapter.

• Anti-authority: Follow the rules. They are usually right.
• Impulsivity: Not so fast. Think first.
• Invulnerability: It could happen to me.
• Macho: Taking chances is foolish.
• Resignation: “I’m not helpless. ?I can make a difference.