If self esteem is an issue, if you need constant praise, if disapointing someone is going to send you into hysterics, then you should not be in service to someone else.*

I don't belive this to be true.. Sometimes the Dom(me) in charge causes this reaction, due to incorrect discipline, etc. I know in my previous experience it was that way. Does that mean I should have never had the experience of my second relationship? I think not.
I believe reenforcement is part of the whole process. If you don't get the required amount, then there's a problem. Yes, I do believe some of this should be internal, but if a Dom(me) never gives any reenforcement but dissapointment and discipline, then of course you're going to be in hysterics when something goes wrong!
I have also found that during relationships, my self esteem is higher than at any other point in my life. I think if you feel inside you the will to serve, then you will serve. If the will is not there, then yes, you shouldn't be a submissive. Stick to topping or bottoming.