If the appraisal comes in higher that what you offered you did a good job.
If the appraisal comes in lower you got to excited.
If the appraisal comes in about the same then you offered about what was expected.
If your offer is more than the appraisal and you had an appraisal contingency then you should either 1 walk away or 2 have the seller drop their price to the appraised value OR LESS. No one should overpay for a house. It is bad enough they are likely to drop even further in value over the next 2-3 years. Overpaying now just makes that feel even worse.