What is the propriety of an affidavit containing unsworn letters that express an opinion about the conduct of the other side?

I will digress briefly to comment on the propriety of placing this type of material before the court. The frequently quoted remarks of Spencer J. in Creber v. Franklin, [1993] B.C.J. No. 890 at ¶19 and ¶20 (quoted partially) are apt: ¶ 19 There are unsworn letters attached to the affidavits that express the opinions of their authors. Save where they may be admissible as expert opinions they are inadmissible. There are adjectival descriptions by one side of the alleged acts or statements of the other. They are irrelevant. The affidavits should state the facts only, without stooping to add the deponents descriptive opinion of those facts. It should be left to argument to persuade the trier of fact what view he or she should take of them. For counsel to permit affidavits to be larded with adjectives expressing an opinion about the conduct of the other side contributes nothing to the fact finding process. On the contrary, it does a disservice. It exacerbates existing ill feeling, it pads the file with unnecessary material and it wastes the court's time. ¶ 20 In this material there are descriptions by the petitioner of how he views some of the respondent's actions. The court is not concerned to know whether he was "shocked" or otherwise offended by what the other did, unless that is made relevant by some condition induced in him which explains some act attributed against him. It is the court's opinion of a party's actions that is important. Self-serving protestations of surprise, shock, disgust or other emotions claimed by a deponent are a waste of time and counsel would do well to remember that.