I am fortunate I live in a very good neighborhood. On 4 occasions since I bought my new car last August I have leaned against the kitchen counter, or something similar, and accidentally pressed the key fob in my pocket and opened my trunk... for all driving by to notice my approximately $3000 worth of golf gear in my trunk. I'll usually discover it an hour or so after the trunk has been open. No, I'm not giving out my address.
A common subject on my neighborhood Nextdoor is smash and grab car burglaries, and often the OP will say something to the effect of "I even hid my laptop under the seat and it still got stolen" or "I just parked and ran into my friend's house for 5 minutes..."
Super annoying aspect of living in an otherwise decent place.
I've got a station wagon, so unfortunately everything in the rear storage area is in plain sight. There is a retractable cover, but I feel like covering stuff almost makes it look like something valuable is being hidden. I do have a driveway, so our car is always parked off the street, and hasn't been subjected to the same amount of pointless vandalism as others in the neighborhood. Now there are even more sophisticated thieves rolling through neighborhoods in vans and quickly cutting the catalytic converters off of Priuses (apparently they are valuable) with cordless sawsalls.