How to prove premeditation and deliberation ? In reviewing the sufficiency of the evidence of premeditation and deliberation, we assess whether the evidence supports an inference that the killing occurred as the result of preexisting reflection, as opposed to an unconsidered or rash impulse. ( People v. Pride (1992) 3 Cal. 4th 195, 247 [10 Cal. Rptr. 2d 636, 833 P.2d 643].) We do not substitute our judgment for that of the jury. Rather, we must draw all inferences in support of the verdict that can reasonably be deduced and must affirm the judgment if, after viewing all the evidence in the light most favorable to the prosecution, any rational jury could find premeditation and deliberation beyond a reasonable doubt. (Ibid.; see also People v. Perez (1992) 2 Cal. 4th 1117, 1124 [9 Cal. Rptr. 2d 577, 831 P.2d 1159].) Pertinent categories of evidence bearing on premeditation and deliberation are: (1) planning activity; (2) motive; (3) manner of killing. (See People v. Anderson (1968) 70 Cal. 2d 15, 27 [73 Cal. Rptr. 550, 447 P.2d 942].) However, these factors need not all be present, or in any special combination; nor must they be accorded a particular weight. ( People v. Pride, supra, 3 Cal. 4th at p. 247.) Rather, the Anderson factors serve as an aid to reviewing courts in assessing whether the killing was the result of preexisting reflection. (People v. Perez, supra, 2 Cal. 4th at p. 1127.) Finally, it is important to keep in mind that deliberation and premeditation can occur in a brief period of time. "The true test is not the duration of time as much as it is the extent of the reflection. Thoughts may follow each other with great rapidity and cold, calculated judgment may be arrived at quickly .. . ." (People v. Thomas (1945) 25 Cal. 2d 880, 900 [156 P.2d 7].)