With regards to CP's, I don't blame them. As a former CP as well, I found it hard to put on that smiley face every day due my roommate situation + job. I had wanted desperately to do attractions - applied for attractions, got Pecos Bill's/Pirate and Parrot.

My roommates were horrible - one would sit in a living room chair, put on headphones and rock her body back and forth so violently that she would nearly knock the chair over. So strange. The other two got along with each other, but were rather mean to me. I got moved from Pirate/Parrot (Tortuga cafe now) to Pecos 1/2 through and meet a great guy and his friends, and had lots of fun those last two weeks. I also got carpal tunnel from flipping over cups, and wasn't able to get medical care. Disney will say that you get out of your program what you put into it, but there wasn't much there to put in. Plus, my managers weren't helpful or caring at all - they just wanted bodies. It felt like a bait and switch - the Disney recruiters saying that you will have so much fun, learn job experience, have Disney look great on a resume. Sometimes it isn't so, and again, when you get that horrid job, facing it every day with no ablilty to move to any other position is really, really depressing. And, did I mention the location # for Pecos was, at my time, 666?
But oh, what a difference a year can make! The next year I decided to apply again, and got MGM. I was assigned to Indy Jones, but through a mixture of me being late to training and having a great trainer, I got to do GMR! I also was put up in a beautiful new apartment (as opposed to the icky original CP apartments), and had great roommates. I even got my own room because the other person in our group never showed up! My managers were awesome, roommates were fun (one of them even had a car! We did group food shopping.), my GRM friends were fun - it was GOOD to be at work! Hence, I was much more smiley,

, and it made it easy to be at work - not a horrid experience. People at Disney, management at Disney makes all the difference for the CMs. Happiness does come from the top down - even the park manager for MGM at that time was supportive of all his CMs - he expected excellence from all of us, and he also applied that to himself. No one was too big or too small - he treated everyone equally.
And again, I got from the program what I put in - fun and a great job experience as opposed to being treated as a body like at Pecos.
Also, keep in mind that I didn't believe food service was too menial for me. I think MGM was a better park and our roommates were kinder. Like, one of my roommates worked Parking, and she had a blast. She did a lot of the ride spieling for the trams and would make up different accents to amuse herself. One time, she did a British accent, and had guests asking here where in England she was from! So, you can have fun, be friendly and work hard. But for CPs, I think a lot of it is determined by where you are, your roommate situation (you can't change roommates, it sucks) and your managers.
And that's why you shouldn't blame CPs that much for being unfriendly. Cause sometimes, we just can't leave it at the park, no matter how hard we try. And trust me, my first tour, I tried!