The other day, my youngest daughter (age 17) walks in, looks at her phone, and mutters a phrase that I had never heard before. “TIFU” (pronounced tie – phoo).

“What does that mean?” I asked, expecting (and getting) some acronym that kids have come up with as the next buzzword.

She looked at me, shook her head and said, “Dad…TIFU. Today I f-ed up?” and walked out of the room. She was gone before I could shout back, “Hey! Watch your mouth!” But it got me thinking about how those four letters apply to the intelligence world, and the cost of how “f-ing up” affects us on everything from an individual to a global level. Particularly, how can even the slightest failure in the business of intelligence gathering affect people, policy, battles, and wars?

No one is perfect. Every action or inaction has consequences. These are lessons passed on to me by my parents and often painfully, by my life experiences. These same lessons have been (or should have been) learned by presidents from Lincoln to Obama, and military commanders from Pershing to Petraeus. But “learned” is a subjective term in both worlds, and that subjectivity is universal across history, language, and cultures.

During World War II, the German military prided itself on its ability to both wage lightning war and to stay one step ahead of the Allies. But Operation Fortitude, the false “field army” portion of the larger Operation Bodyguard deception program, so completely fooled the majority of the German intelligence apparatus that the June 6, 1944 landings at Normandy found the Nazi military taken totally by surprise. It was the beginning of the end of the war in Europe.

On 1 November, 1950, thousands of Chinese infantry poured out of the hills near Unsan, North Korea, completely surprising and overrunning the South Korean, UN, and U.S. forces there. Similar attacks took place all along the Korea-China border, but then suddenly, on 6 November, the attacks stopped, and the Chinese forces melted back into the hills and disappeared.

Despite the attacks and information from various sources, General Douglas MacArthur and his Far Eastern Command (FEC) intelligence chief, Maj. Gen. Charles A. Willoughby, continued to insist that the Chinese would not intervene in force. On 6 November, the FEC continued to list the total of Chinese troops in theater as only 34,500, whereas in reality, over 300,000 CCF soldiers organized into 30 divisions had already moved into Korea.

Fast forward to 1998. The U.S. and allied intelligence community is taken by surprise when India, in retaliation for Pakistan’s test launch of a missile with a 900-mile range, conducted three underground nuclear-weapons tests. U.S. intelligence had been closely monitoring the facility in question via satellite and other SIGINT (signals intelligence) measures, but to my knowledge, had no human assets reporting on the government’s intentions. The tests were an embarrassment to the Clinton administration, the CIA, and the intelligence community; they also exposed the U.S.’s over-reliance on technology instead of using HUMINT (human intelligence) as a primary collection tool.