What are some facts that make people believe 9/11 was a government conspiracy?

Here are the commonly cited claims that lead people to believe the September 11 attacks (9/11) were a government or inside-job conspiracy. These are claims, not validated facts; many have been investigated and debunked. I’m presenting them objectively so you can judge the strength of each.

1. The collapse of World Trade Center Tower 7 (WTC 7) resembled a controlled demolition (straight down, into its footprint) rather than a fire-and-impact collapse. (Wikipedia)
2. The impact and fires from the hijacked planes alone could not have caused the towers to collapse as quickly as they did. (Sky HISTORY TV channel)
3. A missile, drone, or non-commercial aircraft hit the Pentagon rather than American Airlines Flight 77, because the entry hole appeared small and plane debris seemed limited. (CBS News)
4. The U.S. military and air-defence (e.g., North American Aerospace Defense Command / NORAD) stood down, delayed intercepts, or allowed the attacks to proceed. (Sky HISTORY TV channel)
5. Significant put-option trading (bets that stock prices would fall) in airline companies occurred prior to 9/11 — implying foreknowledge. (Sky HISTORY TV channel)
6. Some intelligence, warnings, or prior knowledge of hijackings or al-Qaeda attacks existed but were ignored or suppressed—raising suspicion that government knew more than it admits. (Voice of America)
7. The National Institute of Standards and Technology (NIST) investigations are criticised for relying on modelling rather than full forensic disclosure, so theorists argue the collapse explanations are incomplete. (Wikipedia)
8. The think-tank Project for the New American Century (PNAC) had argued before 9/11 for a “new Pearl Harbor” to justify increased military spending and foreign wars; conspiracists see this as motive. (arfjournals.com)
9. The fact that the towers collapsed so completely into dust and rubble leads some to argue that explosives or thermitic materials were used (e.g., claims of “nano-thermite” found in dust). (Wikipedia)
10. The visible “search for survivors” and subsequent swift decision to demolish or clear WTC 7 raised suspicions of cover-up. (Sky HISTORY TV channel)
11. The timing of the attacks allowed the U.S. government to pass laws (e.g., the USA PATRIOT Act) and expand surveillance and military reach; some see this as a motive. (lemontopics.com)
12. The number of initial warnings and intelligence failures (e.g., known hijackers entering the country) feed into the belief that something was deliberately mishandled. (International Business Times)
13. Some official statements and timelines are inconsistent or incomplete, which fuels suspicion of a cover-up. (Program on Extremism)
14. The fact that the towers collapsed into their own footprint (especially Tower 2, then Tower 1) is cited as resembling classic demolition patterns. (Wikipedia)
15. The building owner of the WTC complex, Larry Silverstein, reportedly said “pull it” (interpreted by some as “pull the building”) in a televised interview regarding WTC 7 collapse. (Note: disputed) (Reddit)
16. The rapid transfer of billions of dollars in contracts (e.g., to defence, reconstruction) after 9/11 is viewed by some as benefiting people with ties to the event. (Sky HISTORY TV channel)
17. Some testimonies from first-responders and witnesses claim hearing explosions or seeing flashes that are interpreted as planted charges. (Sky HISTORY TV channel)
18. The presence of ongoing war-games or military exercises on the morning of 9/11 is flagged by conspiracists as enabling confusion and facilitating the attacks. (JOE.ie)
19. Claims that the U.S. government rushed to destroy evidence, restricted access to sites, or cleared rubble quickly—interpreted as preventing independent forensic investigation. (Sky HISTORY TV channel)
20. The distrust in government overall (due to other scandals) makes people more willing to believe that such a major event could have been orchestrated rather than merely allowed. (International Business Times)