Animals become accustomed to food being in traps, so they go into traps expecting food. It is a known phenomenon amongst trappers, I think they call it trap happy?
Racoons are also naturally curious so that might be helped.
In "Where the Red Fern Grows", they describe a homemade trap where a raccoon can reach through a circle of nails and grasp a shiny object like a piece of mirror, etc. Their paw is now too big to fit through it and they are stuck, even though they could let go and leave any time!
On an unrelated note, I can't quit my job because I don't want to lose my health insurance there...
That's because they've been frantically digging at the bottom of the cage, tearing up all the grass. I was trying to catch a groundhog and caught a raccoon instead. Little asshole was the most vicious, savage beast I'd ever seen. He wouldn't even leave after setting it free, he turned around and death glared at me before finally running off.