Not about the apostrophe, but how about this for different meanings then?
Dear Mother,
In law, there is nothing to make me say thank you, but the quality of your gifts compels me at least to write to tell you how I feel. Thank you so much for the presents! I was expecting nothing more than a token yet, again, you have exceeded even your own incredible standards.
It was a shame you had to stay here for such a short time. I thought I might have coped, but it was unbearable seeing you leave. The relief was immense when I heard we might see you again soon. I wanted to end it all by saying goodbye now. I hope I will not have to say it to you again for a long time. If you have the opportunity to spend Christmas elsewhere next year, please do not.
Much love
Matthew
Dear Mother-in-Law,
There is nothing to make me say thank you, but the quality of your gifts compels me at least to write to tell you how I feel. Thank you? So much for the presents I was expecting. Nothing more than a token, yet again! You have exceeded even your own incredible standards.
It was a shame you had to stay here. For such a short time, I thought I might have coped, but it was unbearable. Seeing you leave, the relief was immense. When I heard we might see you again soon, I wanted to end it all. By saying goodbye now, I hope I will not have to say it to you again for a long time. If you have the opportunity to spend Christmas elsewhere next year, please do.
Not much love
Matthew
An example from
http://news.bbc.co.uk/1/hi/magazine/4583594.stm
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