Judicial Neutrality and Bias
The judge must be neutral. This requires that the judge should "confine himself as much as possible to his own responsibilities and leave to counsel and members of the jury their respective functions."
It is not sufficient that the courts simply be impartial, but rather they must appear to be impartial as well.
The appearance of neutrality is "of fundamental importance that justice should not only be done, but should manifestly and undoubtedly be seen to be done".
I judge can "enter the arena" for "the purpose of insisting the counsel move the case forward".
A judge can participate in legal debate, challenge counsel's position and state preliminary views without creating a perception of bias.
Conduct that involves the "[u]njustified reprimands of counsel, insulting and improper remarks about litigants and witnesses, statements evidencing prejudgment and intemperate and impatient behaviour may destroy the appearance of impartiality".
The justice system only works if it has "the respect and confidence of its society". That requires "trials that are fair" and that appear to be fair to the "informed and reasonable observer". 
- R v Torbiak and Campbell (1974), 18 CCC (2d) 229 (Ont. C.A.), at p. 230-231
- Wewaykum Indian Band v Canada, 2003 SCC 45 (CanLII),  2 SCR 259, at paragraph 66 ("the manifestation of a broader preoccupation about the image of justice [because] there is an overriding public interest that there should be confidence in the integrity of the administration of justice")
- R v Sussex Justices, Ex parte McCarthy,  1 K.B. 256, at p. 259
R v Clarke, 2014 NSSC 431 (CanLII) at para 34
- R v Baccari, 2011 ABCA 205 (CanLII)
R v Clarke, supra at para 20 citing Canadian Judicial Council, "Ethical Principles for Judges" at p. 33
- R. v. S. (R.D.)  3 S.C.R. 484