D.M. Drugs (Harris Guardian Drugs) v. Barry Edward Bywater (Parkview Hotel), 2013 ONCA 356:
 The duty of a trial judge to give reasons was explored in the Supreme Court of Canada's seminal decision in Sheppard. While Sheppard considered the sufficiency of a trial judge's reasons in criminal matters, the same principles were adapted to the civil context in F.H. v. McDougall, 2008 SCC 53,  3 S.C.R. 41. At para. 98 of McDougall, Rothstein J. held that, when assessing a trial judge's duty to give reasons in the civil context, the following four functions should be served:
(1) To justify and explain the result;
(2) To tell the losing party why he or she lost;
(3) To provide for informed consideration of the grounds of appeal; and
(4) To satisfy the public that justice has been done.
 At para. 99, Rothstein J. adopted the reasoning of Binnie J. in another criminal case, R. v. Walker, 2008 SCC 34,  2 S.C.R. 245. In Walker, Binnie J. expanded on the concept of sufficiency of reasons. He explained that the duty to give reasons "should be given a functional and purposeful interpretation". At para. 20, he stated:
Reasons are sufficient if they are responsive to the case's live issues and the parties' key arguments. Their sufficiency should be measured not in the abstract, but as they respond to the substance of what was in issue.
 Put another way, the functions served by a trial judge's reasons are fulfilled if the reasons for judgment explain the basis for the decision reached: see R. v. H.S.B., 2008 SCC 52,  3 S.C.R. 32, at para. 8. As long as the reasons of the trial judge demonstrate why he arrived at his conclusion, this court will not interfere.