Prediction is very difficult, especially about the future.

The above quote is also attributed to various humourists and the Danish poet Piet Hein: "det er svært at spå – især om fremtiden" | It is also attributed to Danish cartoonist Storm P (Robert Storm Petersen). | In an investigation by The Quote Investigator, the earliest version found was in a 1948 volume of the autobiography of Danish politician Karl Kristian Steincke. Steincke had a section on "parliamentary howlers", including an unattributed Danish-language version of the quote said to have been spoken in the parliamentary year 1937-1938. The earliest English appearance of the quote found by QI was in the 1956 publication "Journal of the Royal Statistical Society. Series A." Here the quote was again unattributed, with the author writing "Alas, it is always dangerous to prophesy, particularly, as the Danish proverb says, about the future."

It's hard to make predictions, especially about the future.