Gemini 8 was the thruster incident.

Apollo 1 was an engineering and manufacturing disaster.

It was caused by..... (drum roll)..... unwarranted haste.

Deadlines. Pressure. Economics.

Most agree after the fact that the Apollo 1 accident was not only inevitable, it was necessary and required for the ultimate success of the program and achievement of it's goal.

The saddest fact is that lessons are frequently temporary, and we have to relearn them.

"The price of good shotgunnery is constant practice" - Fred Kimble