ELI5 Inflation - why do we need a little of it?

Why are too little inflation as well as too much inflation both bad? What is the gold standard? Why did almost all countries abandon it in the 20th century?   ... We explain like i'm five!   Thank you to the r/explainlikeimfive community as always and in particular the following users whose questions and comments formed the basis of this discussion: yellowjacketcoder, bruceleefuckyeah, gradenko_2000, fencerman, silent-ambition1399, workingatbeingbetter & obamanibblesnomaam To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Send us an e-mail: [email protected]