Some interesting things that people are certain about:Religion
You have an invisible friend who is the most important being in the world and responsible for everything that happens.Science
The great strength of science is that all its findings are provisional and subject to revision at any moment if new evidence comes in. This is why you should trust it.Economics
Even 0.1% growth over a few tens of millenia would result in an economy bigger than the known universe. But, although it is impossible in the long term, the critical thing is that the economy should grow, otherwise catastrophe will ensue.Love
Exercise left to the reader.