Please look over your withholding on your paychecks so you can enjoy the large refund check again in 2019. The refund is actually your own money paid to the IRS each paycheck, like a forced savings account. But many people count on that check for large purchases and much needed vacations.
The IRS charges an underpayment penalty if you didn't submit the lesser of the 90% of the current year's tax liability or 100% if the prior year's tax liability. Since the IRS played games with the refund checks and many people owe, the IRS graciously lowered this percentage to 85%.
Remember to check you withholding now so you can properly plan for next tax season so you don't have any surprises.