I left because I found a better job. It wasn't hard. I'm a better father and husband since I've left. I make more money, have a better title and career path, don't work impossible billing or service issues any longer, work less hours, sleep at night without taking sleeping pills, drink less, exercise more, have lower blood pressure and am a different enough person that my father says "I can't believe you're back" from time to time when we see each other or talk. It hurts to realize in hindsight that I was so messed up by this company that my father sees a night and day difference in my presence since I've left.
If you're happy where you are, good for you, but realize this company is no longer loyal to long term employees. You're extremely unlikely to retire from AT&T unless you're retiring in the next few years. Better is only the plan for shareholders, not for employees.
If you're thinking about leaving, go but take your time and make the right choice. The grass is actually greener on the other side.