I can't tell you how much this means to me/ how much I love you/ how great God is
You just didI suppose if the first speaker said, "Ha ha you're right" then there might not be a problem, but otherwise I think the response fails to take seriously what the first speaker is saying. It adopts, or pretends to, a kind of meta position outside that language game in order to pass judgment on, or analyse, it, while simultaneously pretending to be making a move in the same language game by contradicting the speaker with an implicit "Yes you can." The first speaker's words are taken as a unit meaning something like "This means a lot to me/ I love you a lot/ God is really great." But what if the speaker denies that that is what he/she means? It seems unWittgensteinian to me to tell them they are wrong about what they mean. Perhaps more seriously, I think it is usually false to tell them they are wrong. Usually when people say something like this there is something they cannot do. So far they have failed to find words that express their meaning to their satisfaction.
This taking of words as a unit seems like a kind of sealing to me, closing the individual words off from attention, treating them as irrelevant. Sometimes that is a good move. The other day someone asked me "What's new?" and I made the mistake of trying to tell him. All he meant was Hello. But sometimes the meanings of parts of the sentence matter.
There is what seems to me a similar kind of sealing off when a religious experience is treated as simply an experience, perhaps with an "as if of" quality about it but without any actual intentionality or content that points beyond itself. Bracketing, I suppose, is the word for this. And it's problematic, because if someone says "I saw God" they don't mean "I had an experience as if of seeing God," just as if I say "My dog is on the sofa" I (probably) don't mean "I am having a visual experience as of my dog on the sofa." I'm not saying that people who claim to have seen God must have really done so, or ought to be assumed to be saying something true. But if we take "seeing God," for example, as the name of a certain kind of experience that can be understood on its own, as if the experience itself were a kind of thing that could be studied in isolation, sealed off from everything else, then I think we go wrong. Or at least we run the risk of doing so. We are (potentially) no longer treating the words as spoken as they were meant. This is probably not a good idea if we actually want to understand them. It also suggests a bad, patronizing attitude toward the speaker, as if we know better than they do what they mean. We might in some cases, but surely shouldn't just assume that we do.
This all seemed quite simple and self-evident when I first thought about it, but writing it down has made it seem much less clear. I hope it make some sense. Just in case it doesn't, I'll try to retrace the steps that led me to these thoughts, although this risks repeating things I have already said. I have heard DZ Phillips criticized for suggesting that an apt response to a statement along the lines of "I can't say how much..." is "You just have." I don't have a reference to hand, but if he did say this then I agree that he was wrong (at least with regard to some cases). Sometimes "I can't tell you how much this means to me" means no more than "This really means a lot to me," and the word 'can't' should not be taken to refer to any inability. Instead it should be taken together with the rest of the words in I-can't-tell-you-how-much, which collectively mean something like: A lot is what (this means to me). Correct understanding depends on not breaking the 'can't' out of its implicitly hyphenated, blister-packed whole.
But not every case is like that. Words don't always come easily, if at all. Treating words as if they are always parts of ready-made wholes misses this, leading to a superficial understanding of sentences and the people who utter them. If someone says "I can't tell you how much I love you" and you reply "I love you too" then you have failed (perhaps justly, but perhaps not) to take their words seriously.
And it seems to me that there is something similar going on when an experience that is most naturally described as an experience of God, an experience that implies that some kind of religion is true, is treated (perhaps by the very subject of the experience) as a pleasant hallucination, as something with no real implications at all. I don't mean that it is a mistake (or a crime) to treat religious experiences this way. All I'm saying is that writing off a (seemingly) religious experience as something not really religious after all is denying it the implications and the importance (the significance in two senses of the word) that it at first, when the experience happened, appeared to have. This means sealing it off from the rest of your life (instead of, say, making it the start of a new life) and treating it as a relatively superficial event. That might be the best thing to do, but it is a sealing off, a denial of significance. And that is what makes it like the "You just did" response.