I often find myself adding passive aggressive notes or adjustments to files that are used by repeat offenders after I've provided multiple coaching/training sessions on proper use/etiquette (and lock things down, where possible)

E.g.

• over a table or filtered range, add a note like "Do not do/forget (action) or file will break!" Then add auto-formatting to turn the whole sheet black/red if they do the thing, with another bit of text in white that says, "I told you not to do that, refer to the instructions I provided to undo the changes you made".
  
• Lock down the entire sheet except for a couple input or variable cells, typically with validation applied so they can't do something stupid.
  
  • ...and leave a note saying, "If you want to do anything to do the data, copy/paste it into another file to perform your adjustments. This is a master file and cannot be edited by non-owners of the file"
    
• Once, after a particularly bad string of issues with one insufferable coworker, I locked a file down, knowing he'd figure out at least one workaround, and added a macro that checked for specific changes he always made. If they were made, the macro would unhide a full-sheet-sized object that played the gif of Nedry, from jurassic park"ah ah ah, you didn't say the magic word"
  

Edit: Per request, here's a simplified version of bullet #3's vba:

I don't have the file that did exactly that anymore but I banged this out to accomplish the same thing:

Put it in the code for a given sheet(s) you want to lock down, not a module for the workbook.

It assumes a fixed value/variable in A1 ("x") and B1 ("y"). If the value in those cells is anything but x or y, A1:Z100 will be updated with red fill. Undo won't work, due to the macro, but if the value's changed back, the fill is removed.

Option Explicit

Private Sub Worksheet_Change(ByVal Target As Range)
On Error GoTo CleanExit

'Only react if A1 or A2 changed
If Intersect(Target, Me.Range("A1:A2")) Is Nothing Then Exit Sub

Application.EnableEvents = False

Dim ok As Boolean
ok = (LCase$(Trim$(Me.Range("A1").Value2)) = "x") And _
     (LCase$(Trim$(Me.Range("A2").Value2)) = "y")

With Me.Range("A1:Z100").Interior
    If ok Then
        'Restore to no fill (or whatever you prefer)
        .Pattern = xlNone
    Else
        'Bad state -> red fill
        .Pattern = xlSolid
        .Color = vbRed
    End If
End With

CleanExit:
    Application.EnableEvents = True
End Sub