I think it's like kids - they'll do whatever they know they can get away with. They aren't born (kids or cats) knowing that they should/shouldn't do something.
Discipline and abuse are not the same thing. Due to DH's allergies, our cats have always been allowed in kitchen, laundry, family room, but NOT in the living room or bedrooms. No door between living room and family room, we just taught them it was off limits, as were the counter, table, stove, refrigerator. A loud clap and sharp "NO!" is really all that was needed, and we've had several cats over the years. The thing is, you can't waiver when they are little - you have to be consistent, even if they are so cute you'd really rather not be the meanie.
Well, I should admit that now that we are down to one (and DH says no more pets :cry: ) and he is older, he is allowed to sleep on my side of the bed.