If my rent goes from 1000 a month to 1500 a month from one year to the next, that’s 50% inflation. If it stays at that higher amount for a full year afterwards, that’s 0% inflation. But that doesn’t mean I’m suddenly living the good life. I just went a full year with my rent way higher than I used to pay, and my income did not increase proportionally. I am able to save less (if at all), can’t afford things I used to be able to, and feel just a little more desperate every month.
That’s why looking at year-over-year inflation is meaningless. It doesn’t reflect the long-term hardships that come from a sudden price spike that never goes back down.