The prosecution may not “over-prove” its case and the court’s admission of evidence of numerous uncharged crimes not resulting in convictions, pursuant to Evidence Code section 1101, subdivision (b), was an abuse of discretion. Appellant was prosecuted for drug and weapons offenses and related gang crimes and enhancements. The prosecutor introduced a considerable amount of evidence dealing with appellant’s prior contacts with law enforcement, justifying it as being admissible pursuant to Evidence Code section 1101, subdivision (b); as well as to prove gang offenses, and for impeachment. In considering the alleged errors dealing with the presentation of cumulative evidence, the court observed that the unnecessary quantities, which extended a routine weapons and drug case into a weeks-long marathon, were plain error as inadmissible under Evidence Code section 352, but resulted in harmless error.