This little macro will clear any cell that contains "sadness":
Sub MakeHappy()
Dim rr As Range, r As Range
Dim s As String, rClear As Range
Set rr = ActiveSheet.UsedRange
s = "sadness"
For Each r In rr
If InStr(r.Value, s) > 0 Then
If rClear Is Nothing Then
Set rClear = r
Else
Set rClear = Union(rClear, r)
End If
End If
Next
If rClear Is Nothing Then
Else
rClear.Clear
End If
End Sub