Like Gloria, I can only speak from my own point of view. Unlike Gloria, I don't think a Dominant is weak if He pushes your limits. But that also depends on the instance.
In my experience, I have been grateful to have my limits pushed. In learning one another, he discovered my limits quickly, and every once in awhile, one just pops up out of the blue. It is my personal opinion that most limits should be pushed and extended. I say most limits because there are exceptions. Some we cannot control. One example, I am very weak in the stomach. I cannot even to tend my kids bloody noses. God help me if it happens and someone else isn't with me. So therefore, knife or razor play is not part of our lifestyle. Yet. We tried once, and I almost passed out. But as a submissive to the core, to please him, I would have happily passed out. But that wouldn't have pleased him. My well being is important to him and what good is a submissive passed out on the floor because of her own physical limitations? Physical limitations should not be pushed, that is a weak dominant. But they should be nudged. Because, physical limitations are a weakness and they can be overcome. He has SLOWLY worked on this with me, but as soon as he senses my lightheadedness, he stops. It is with great jubilation I say that it takes longer for him to have to stop each time. He isn't being disrespectful of my limitations, he is in fact making me stronger, slowly and steadily. So that way, should there come a time in my life when I have to deal with that bloody nose or broken arm, or vomit, I am better equipped and handle it. He pushes me to make me a more able person in all aspects of life.
Now personal limitations that catagorized as emotional or mental should be pushed and conquered. If it is emotional or mental it needs to be pushed and given to HIM. It doesn't have to be a problem for you. Give it up! Give it to him. Let him deal with it. IT IS NOT YOUR PROBLEM! Yes it is hard. Yes you may hate that he is pushing you. Yes you may question your own submissiveness. But in the end, you are opening yourself more to him and giving more of yourself to him. That is all we really want, right? I am claustrophobic. This is a mental limitation. A very scary problem. Can you imagine a claustrophobic submissive? But he pushed that in me. He talked to me gently with words of encouragement, taught me how to breathe, helped me to realize that nothing was going to happen to me just because my arms and legs were tied. This comes with trust too. You must trust in your Master to carry you through these difficult times. It was a long process, but now I can face these hard situations. He can hog tie me in a tiny little attic space and leave me to face it and I will be just fine. I don't like it, but I gave that weakness to him and he helped me overcome it. And for that, and other instances like that, I am forever grateful.
IF your master loves you, and is concerned for your well-being, and wants you to be a stronger person, he will push you and your limits. But there must be a reason for everything! One hard limit I have, which he will never push is alcohol enimas. We did it twice and both times I vomited violently. This is major medical! You can either hold your liquor or you can't. He recognized this as something that could not be overcome, and that it was something that had no real reason. The fact that I was willing was all he needed from me. So we won't go there ever again.
That's the key. Be willing. Be obediant. But you must trust that he knows when enough is enough. If you aren't that trusting, than of course, you just haven't gotten that far in the journey. But being submissive means giving all you can and not holding back. Limitations and all. Being dominant means taking responsiblity in all aspects of the person who has indeed trusted their life to you. If he isn't responsible, don't push those limits. But if he is, he deserves all of you....ALL OF YOU.