Insurance companies estimate that 20% of house fires in the US are caused by squirrels, or around 30,000 fires per year. They chew on electrical wiring. The worst offender by far is the Eastern Grey Squirrel.
It is bad enough you folks back east have to deal with these bushy-tailed daytime rats. I want to wring the neck of whoever introduced them to Los Angeles. They are not native to the west and we didn't have them here when I was a kid, we should only have native ground squirrels until you get to higher elevations, then only Western Grey Squirrels and Chickarees, which reasonably well behaved, for squirrels.
I regularly lose my internet due to squirrels chewing on the cable. They would steal everything from my fruit trees and like to strip bark off the trees, too, if I let them. I've seen them pulling up my neighbors roof shingles. They also eat the eggs of endangered western song birds, so as biologist, I eliminate Eastern squirrels with extreme prejudice.
Like Geena, I find them very easy to trap, especially using peanut butter as bait. They are completely unwary and unfazed by humans. Sometimes they are on the fence waiting to get in the trap as I am setting it. I use two traps on my property, one at either entry point on the back fence they use as a highway.
Kania 2000
I use this trap. It is the most humane kill trap I could find. Please do not us a live trap and release somewhere else. That is illegal. If you use a live trap, be prepared to shoot or ether gas the squirrel. I give my dead squirrels to my neighbor who feeds them to his monitor lizard (saves him from buying poor bunnies to feed it).