I often say that with one mistake in life, we have to invest our whole life to correct it. This is not possible when we make mistakes in cross stitch. The border is particularly challenging. One initial mistake in calculation will end up with the border not connecting at the other end.
You can see it in this cross stitch; the border does not connect and the gap between the central rose is not even.
So I have a lesson to learn even through art.
And some others: