And because they don't only get stuck by their feet, like their face, for example. If you're only planning on catch-and-release, then use a trap made for that. How silly do you have to be to glue them to a piece of paper, just to intend to un-glue them later?? That alone is cruel.
After the rat was caught, I had read about how they slowly suffocate over days, often chewing off their own limbs in a largely futile attempt to escape.
I ended up bludgeoning the rat. I still remember the high pitched scream it made upon receiving the first blow. It only lasted about a minute but it was a pretty fucked up experience, and that was going the merciful route.
How many times did you hit?
Definitely don't use poison. It's not painful for the rodents, but it makes its way up into the food chain. Mountain Lion P47 in CA is alleged to have died from rat poison ingestion.
https://www.youtube.com/watch?v=zMAzyDDAppU
There doesn't seem to be a lot of distress/trauma involved -- in fact, if you watch to about 2:54, there's a rodent that apparently successfully avoids the trapdoor action and then more or less appears to think to itself "hey, what's down here, maybe I'll join the party."