What I expect from a CW QSO to make it decent and enjoyable is as follows. This is what I am examing myself in usual QSOs.
1) Make the message simple and plain. CW is the least efficient communication mode as for the amount of message sent in a unit time. The message should be simple and the topics per a transmission should be limited to 2 or 3 at most. If the message is lengthy and covers more than 4 topics, it is always difficult to follow. In the condition with much QRN/QSB, each sentence should be as short as possible. Such sophisticated expressions as rhetorical question, irony or subjunctive mood are not appropriate in such situation. Expressing an idea with simple and plain sentence is a highly intellectual process, isn't it?
2) A QSO should not be a two way monologue but a real dialogue. This won't restrict what you talk about. I am always enjoying what a good friend of mine reports me how he/she is getting along. But if the QSO ends with only that, it is not what I pursue in QSOs. I hope the other to listen to what I say and to respond to it. The problem is if the eyes are directed not toward his/her own mind but toward the others. Asking "How are you doing?" in the end of a transmission is good enough.
Nowadays, it is rather difficult for me to find anyone who would make conversation on this mode. It is a problem before this discussion. But if I could meet someone who would converse, he or she would make monologue too often. In my case, I have the problem of language. Writing down this post, I could not help feeling ashamed to present here this problem in this way. Because it is questionable that I have filled these things by myself. I would brush up myself and make decent memorable QSOs.