[recursivecaveat]

Part of it is just expectations btw. If the value of money is jumping up and down rapidly it is bad for business. Like if I'm going to sell you a 30 year fixed rate mortgage we require an accurate expectation of future inflation for one of us not to effectively lose their shirt on the deal. Imagine shops shuffling their prices up and down constantly, unions renegotiating contracts all the time, you sign up for 12 months of netflix but the price implicitly assumes that money will be worth N% less by month 12, etc. (imo a lot of these things should already be pegged, but people don't like doing that) It's basically just much more annoying to transact using a currency whose future value is unpredictable. So given that 2% is the stated target, which expectations are presumably largely built around, significant deviation is a failure to manage that process.