What causes the Mandela Effect flip flops? No I'm not talking about sandals here.

Like the Flin(t)stone ME or "Houston we ha(ve)d a problem,etc. Why do some flip flop and others don't? Why does CERN care so much about some stupid random spelling? Why not change actual history like the Titanic avoiding the iceberg and making it to the foggy New York City? Perhaps control the weather to make the artic high pressure that created the conditions not happen? How about stop 9/11 on a more recent effect?

Why do stupid stuff?