I love "Ride it like you stole it" too!

I only use a mantra when riding up hills - and it's always one of these two:

1) "Pull, pull, pull" (which reminds me to use a full stroke and truly engage the upstroke). I'm waiting for the day when a full stroke becomes intuitive, no mantra needed

2) "I am strong and getting stronger all the time" (really goofy , but when the hill is steep and my speed/cadence had slowed to that "yeesh, any slower and you'll fall over" point, I remind myself that I've got strength i don't even know about yet.