And the IRS changed the withholding tables so you got more in your checks during the year instead of a big refund. Or there are other tax changes. And any dependents you have are a year older. If you made more income that can reduce some credits you got like the EIC.
Here's a good FAQ on why your refund might be less than last year
https://ttlc.intuit.com/community/refunds/help/why-did-my-refund-go-down-compared-to-last-year-s/00/...
