Excel

The macro recorder likes producing this sort of code.

    Range("E13:G16").Select
    Selection.Font.Bold = True

This is evil.

Here is why.

Bundle the code up in a subroutine

Public Sub Highlight()
    Range("E13:G16").Select
    Selection.Font.Bold = True
End Sub

Seems reasonable.

However lets say we have another subroutine

Public Sub FormatCells()
    Range ("A14:B20").Select
    Highlight()
    With Selection.Interior
        .ColorIndex = 7
        .Pattern = xlSolid
    End With
End Sub

The idea is that we want to set the colour of the sells A14:B20, and highlight E13:G16.

Sorry, it doesn't work. You cannot nest the calls, because of the .Select statement. It changes the selection and is a side effect of the call to Highlight. The end result is you cannot decompose your subroutines in this way.

The code should be this

Public Sub Highlight()
    Range("E13:G16").Selection.Font.Bold = True
End Sub

Public Sub FormatCells()
    Highlight()
    With Range ("A14:B20").Interior
        .ColorIndex = 7
        .Pattern = xlSolid
    End With
End Sub

This is now side effect free.

ie. Remove all the .select / .selection from the code.