How have courts treated allegations of judicial bias?

Appellant's accusation of judicial bias is based on her claim that the juvenile court erred in making critical factual findings against her. However, "expressions of opinion by a trial judge based on actual observation of the witnesses and evidence in the courtroom do not demonstrate a bias. [Citations.] Moreover, a trial court's numerous rulings against a partyeven [if] erroneousdo not [alone] establish a charge of judicial bias . . . ." (People v. Guerra (2006) 37 Cal.4th 1067, 1111-1112, disapproved on another point in People v. Rundle (2008) 43 Cal.4th 76, 151.) Opinions formed by a trial judge on the basis of facts introduced or events occurring in the course of the current proceedings do not support a claim of bias "unless they display a deep-seated favoritism or antagonism that would make fair judgment impossible." (Liteky v. United States (1994) 510 U.S. 540, 555 [127 L.Ed.2d 474, 491].)