Can you boost my understanding of Access? I don't like things I can 'cure' but don't understand why!

I've converted the Save macro on my form to VBA. It looks like this ... as I'm sure you already know.

Code:
Private Sub SaveChanges_Click()
On Error GoTo SaveChanges_Click_Err

    On Error Resume Next
    DoCmd.RunCommand acCmdSaveRecord

SaveChanges_Click_Exit:
...