A short paraphrase from C. S. Lewis' Miracles, in my own words:
The nature of miracles is confused. People hold the belief, and for sound-albeit narrow-reason, that no perfect God would intrude upon this world and alter it in such a way that the bible tells. A perfect God would never need to add to his masterpiece. There's a similar camp which suggests that the “Natural World” does not need intrusion by a deity, and in fact rejects such intrusion. Now, I will answer these two claims, the second simply (and first), the first in a more complex way later.
The Natural World cannot reject an intrusion from the supernatural, much in the same way a “chair” cannot keep “someone” from sitting in it when said “someone” chooses, so long as this “someone” created the “chair” to be sturdy enough to support said “someone” (for, this “someone” is a very large, and powerful “person”. It takes a strong world to support Him). In fact, this “chair” oftentimes benefits from this “someone” sitting it it; its purpose is being fulfilled. In fact, this “someone” who made this “chair” is so skilled that the “chair” is, in a whole sense, invulnerable to any degradation or rot. A leg may break, but “someone” always fixes it to make it whole. The “chair” enjoys the creator's sitting, and fixing.
Secondly, this gets more difficult to explain (and that chair metaphor was tough to fill in the holes (i.e., “invulnerable chair”)). After all, I simply explained that Nature won't reject nor can reject God's “interference” or “intrusion” (indeed, it's more like a good King checking in on his serfs(constantly); they run out and greet him). It gets more convoluted attempting to explain the reason behind God's need to “intrude”, and I bring you to my friend. He's read through the first book in a series, and enjoyed the political intrigue. He assumed the other books would be full of the same machinations as the first one, an indeed it seemed the first book's ending fed directly into those assumptions. Though the author was much more interested in the first book leading into what he described as a book with “too much magic, not enough political intrigue”. Apparently, the gloriously famous book was more unlike the rest of the series, and this turned off many a fan.
Throwing another example into the mix, pick any outrageously famous poet, author, or artist you heard about in grade school. Remember how you noticed that they disobeyed rules that you were sure were set in stone, the most basic rules of the skill? Robert Frost was made an enemy for the longest time in my eyes with his piece, Mending Wall. Frost, in my eyes, ignored all functions of common poetry, writing a badly metered jumble of words (which I later came to recognize the beauty and flow of) that I could not stand. I complained to the teacher, asking how he could pass off the piece as poetry. In another case, I was infuriated at Shakespeare – how dare he make lines that make no sense; how dare he throw words of his own in the mix! In both cases, the artist had proven himself far superior, and was able to have more leniency in their pieces. In fact, these pieces became some of the most memorable pieces in their careers, and in my childhood.
Let's go back to the book series. My same friend went through the entire series (he is apparently a Masochist), muddling through all the magic fluff. He went back to me later, and praised the series. He said that the series turned around, that the magic actually led back into politics, and the two synthesized to make the story more massive than he believed. It was in reading further into the complexities that he understood that the author of this series, this creation, was using an entirely different storyline, using different rules than my friend has presumed. This mirrors many people's thoughts on miracles all too well, though they sadly do not take the extra step and read more deeply.
Last point, and I’ll close. The skepticism due miracles is because we view them as superfluous, with no goal, simply “a fluffy good deed”. Much like my friend above, they read into the first small bit of the creation they see, and use the rules viewed—the perspectives seen—to write their limits on God. But we are not the main story, and miracles are not aimless. If miracles do exist, then they are the heralds of every new chapter in the Book of Life. They are momentous occasions, which have been set forth from the Most High. Miracles are God's creative license, and, much like grade school children, we only see them as breaks from the norm (much like Frost's poems) and berate them for the author's “lack of ingenuity”, or “lack of skill” in the “blunder”. But, much (much, much) more than Shakespeare and Frost, God's poetic licenses are what make Him unique, inspirational, memorable, and ingenious.