Veronica
It's kind of weird, huh? Hoping Lamb is competent, rather than betting he's not.
Oh, where to even begin with these two?
After the very public investigation of Lilly Kane's murder and humilation of Keith Mars, Don Lamb took over as Balboa County Sheriff. Unlike Keith, Lamb often sided with Neptune's rich and fabulous. Sort of a corrupt authority figure type of guy.
The daughter of Keith Mars and best friend of Lilly Kane. She dealt with her best friend's death (and with Neptune hating her father) by crashing Shelly Pomroy's end of the year party. Veronica didn't really remember the party, but waking up the next morning, she realized she had been drugged and raped.
The morning after Shelly's party, Veronica made the walk of shame into the Sheriff's department to report her rape to Lamb. Unfortunately, Lamb was no longer Keith's subordinate and rather than helping Veronica, he mocked her and asked why she doesn't just "go see the wizard? Ask for a little backbone." Maybe there was more negative interactions between them prior to this encounter, but that day is obviously very significant in their hostility towards each other. Though, they rarely ever mention the issue of Veronica being raped.
Over the next few years, Veronica Mars and Don Lamb continue to butt heads (often keeping with the mocking tone of their relationship). Veronica sees Lamb as incompetent, and Lamb sees Veronica as a troublemaker. However, he acknowledges that she is extremely capable and shouldn't be underestimated. Very rarely have Lamb and Veronica seemed to be on the same side. Veronica and Duncan Kane were investigating Meg Manning's claim that she had been babysitting a victim of abuse. They were caught breaking into the Manning home, where they discovered that Meg's little sister was the child in question. However, instead of arresting Veronica and Duncan, Lamb let them go and kept a watch on the Mannings. One of very few instances where Lamb and Veronica cooperated on some level.
Throughout the series, Don Lamb and Veronica Mars continued to dislike each other (which was usually pretty amusing). Sadly, they never had a chance to settle their ongoing dispute or put the past behind them. Lamb went to investigate a breaking-and-entering call, hoping to catch Steve Batando (a suspect in the murder of Dean O'Dell and ex-husband of Mindy O'Dell). There, he was confronted by Batando, who struck him in the back of the head. Later, Keith and Veronica learn that Lamb died while in Intensive Care. Though they never actually liked each other, Veronica was clearly shaken by Lamb's death.