I brought home a hooded rat from my 7th grade science class at the end of the school year. I thought my mom was going to run away from home. Let's just say she was NOT happy!
My dad however, became very close to "Rover". He did side jobs in the basement every night fixing stereos and other electronics and because there was a cat upstairs, Rover's cage went downstairs so he became dad's "little buddy". (I ended up being allergic to him.) He told the guys he worked with about "his" pet rat (they all thought he had lost his marbles too until they realized he was serious about how intelligent and friendly he was). Rover would sit on his shoulder while he worked and walk around the table checking out all the tools and various parts.
As with most lab rats, he developed tumors several times over the years and our vet dutifully removed them (again, thinking we all must be nuts) but eventually the cancer won out and mom had to take him to the vet to have him put to sleep. Dad was crushed.
They make wonderful pets if they're cared for right!