Occasionally, after editing a feature class the spatial extent (a.k.a. bounding rectangle) associated with the feature class is not updated. This means that if you had a feature class of Utah National Parks and when you loaded the data initially, you accidently included Yosemite NP in California as a feature, a Zoom to Layer command would zoom to a much bigger geographic area, even after you deleted the Yosemite Park feature. Here's how to use it:

1. Paste this script (below) into ArcCatalog's VBA editor (Tools --> Macros --> VBA Editor)
2. Back in ArCatalog, select the feature class in the Contents tab view (not in the left hand tree view)
3. Back in VBA Editor, click your mouse anywhere in this new script and hit the run button (blue triangle)

Public Sub updateFCExtent()
  Dim pGXApplication As IGxApplication
  Set pGXApplication = Application
  
  Dim pGxObject As IGxObject
  Set pGxObject = pGXApplication.SelectedObject
  
  If Not TypeOf pGxObject.InternalObjectName Is IFeatureClassName Then
    Exit Sub
  End If
  
  Dim pName As IName
  Set pName = pGxObject.InternalObjectName
  Dim pSchemaLock As ISchemaLock
  Set pSchemaLock = pName.Open
  
  pSchemaLock.ChangeSchemaLock esriExclusiveSchemaLock
  Dim pFeatureClassManage As IFeatureClassManage
  Set pFeatureClassManage = pSchemaLock
  pFeatureClassManage.UpdateExtent
  
  Exit Sub
  
ErrHandler:
  pSchemaLock.ChangeSchemaLock esriSharedSchemaLock
End Sub

'SRC = http://edndoc.esri.com/arcobjects/9.2/ComponentHelp/
esriGeoDatabase/IFeatureClassManage_UpdateExtent_Example.htm