Schopenhauer's stormy relationship with his mother is well known and the copies of two letters (below) from her are witness to this. I also include three of the letters sent to the 15-year old Schopenhauer by his father: this was when Schopenhauer was at school in Wimbledon. Regrettably, none of the letters written by Schopenhauer in this period have survived. Nonetheless, the ones from his parents give an idea of the trials of the young Schopenhauer during the first part of his teen years. As Bridgwater notes:
'It is impossible to read the letters addressed to Schopenhauer at Wimbledon by his parents without feeling sorry for him. His mother's letters are totally self-centered, his father's grotesquely fussy'. (p.233)
NB. The correspondence to Schopenhauer from his parents during the time of his schooling in Wimbledon in 1803 can be found in Patrick Bridgwater's Arthur Schopenhauer's English Schooling (London: Routledge, 1988).

Edinburgh, 26 July 1803.

Dear Son,
I must say that I am very surprised, and even worried, that we have only just received letters from you, whereas it was made clear to you that you were to write once a week. A week ago today your mother sent you a long letter which I beg you to take to heart; otherwise I shall be extremely annoyed, for writing is something you really must learn to do properly; the other things are unimportant by comparison. Mr Drewe will give you anything you may need; in August I am allowing you to spend one day a week in London, but no nights, and I urge you to behave yourself and to be careful at the riding school, and otherwise to write once a week, on decent paper and John Wm Anderson, Drewe & Co. will always send your letters off straight away, and now God be with you.

Schopenhauer.

Mr Arthur Schopenhauer.
to the Care of the Reverend Mr Lancaster at Wimbledon Commons
Wimbledon
[date stamp: 7 o'clock, Jy 29 1803 N.T.]

Bristol 25 August 1803.

My dear Arthur,
Your mother is not very satisfied with your last letter, and since I have absolutely no note paper this evening I will just saying reply to yours of 14th instant that you need a great deal of practice if you are going to be able to write a fluent and manly hand; that means leaving out all the fancy flourishes; kindly note the capital letters which I have underlined and in future copy them. The swimming lessons seem to me both dangerous and pointless. In drawing and singing you are bound to make some progress since you are already embarked upon them and you are due home in London on Michaelmas Day, 29 September. I want you to acquire the best and clearest German hand and to send me a reply which will satisfy me.

Your father

Heinr. Floris Schopenhauer

Mr A. Schopenhauer Esquire.
to the Care of the Rev. M. Lancaster at Wimbledon Commons
[date stamp: 10 o'clock, Au 27 1803 F.N.]


London. 2 Sept 1803.

My dear Arthur,
Two months ago today we left London and have since travelled 1600 miles; now we are back again and shall be staying here at least until some time next month. You can come to us on Tuesday morning so that we can see you and take you to the races at Enfield. When your time with the schoolmaster is over, bring me your report, which everybody is sure to be given. Learning to hold the pen in such a way that one can move it just with the fingers, without moving the hand, and can therefore wield it lightly, is the whole secret of writing a good, fluent hand. Yes, you have been in Wimbledon almost 10 weeks now, and by the end of the 12th week I was hoping to see you writing properly and to be able to have you back with us in our present lodgings:
Norfolk Street No 43 - Strand
New Church
You are costing me a lot of money in postage with your letters of the immoderate length; bring them with you when you come on Tuesday and give me more pleasure than you have set out to do so far. Adieu.

Heinr. Floris Schopenhauer

Mr Arthur Schopenhauer
to the Care of the Reverend M. Lancaster
Wimbledon
Common
[date stamp: 10 o'clock, Sp 3 1803 M.N.]

Letter from Johanna Schopenhauer to her son Arthur Schopenhauer, dated 6 November 1807.

‘You are not an evil human; you are not without intellect and education; you have everything that could make you a credit to human society. Moreover, I am acquainted with your heart and know that few are better, but you are nevertheless irritating and unbearable, and I consider it most difficult to live with you.
All of your good qualities become obscured by your super-cleverness and are made useless to the world merely because of your rage at wanting to know everything better than others; of wanting to improve and master what you cannot command. With this you embitter the people around you, since no one wants to be improved or enlightened in such a forceful way, least of all by such an insignificant individual as you still are; no one can tolerate being reproved by you, who also still show so many weaknesses yourself, least of all in your adverse manner, which in oracular tones, proclaims this is so and so, without ever supposing an objection.
If you were less like you, you would only be ridiculous, but thus as you are, you are highly annoying’.

Letter from Johanna Schopenhauer to her son Arthur Schopenhauer, dated 17 May 1814.

'The door which yesterday, after your highly improper behaviour towards your mother, you slammed so noisily is closed forever between you and me. I am tired of bearing your behaviour any longer, I’m leaving for the country and I shall not return home until I know that you are gone. I owe this to my health, for another scene like yesterday’s would bring on a stroke that might prove fatal.
You do not know what a mother’s heart is like, the more tenderly it loves the more painfully it feels every blow from a once loved hand... This I declare before God in whom I believe, but you yourself have torn yourself away from me; your mistrust, your criticism of my life, my choice of friends, your desultory behaviour towards me, your contempt for my sex, your clearly expressed reluctance to contribute to my contentment, your greed, your moods which you allowed free rein in my presence without respect for me, this and a lot more that makes you seem vicious to me, all this divides us...
My duty towards you is at an end, go your way, I have nothing more to do with you… Leave your address here, but do not write to me, I shall henceforth neither read nor answer any letter from you…
So this is the end…You have hurt me too much. Live and be as happy as you can be'.