As a Biblical Creationist, one of the most annoying and cliched things to hear is "the Bible wasn't meant to be taken literally". It annoys me, not because it's not true, but because it is used as an excuse to ignore the parts that very clearly are intended to be taken literally.
The flip side of this is when people take very obviously non-literal parts of the Bible and insist that anyone who doesn't take it literally is not being honest or rational, especially when they follow it up with "therefore, you're not a Christian". The greatest example you can give of this is "this is my body".
I will never understand the insistence upon taking Jesus literally on this one point. I've seen Catholics read it out and say "do you believe Jesus lied here?" My response is often simple: "Then crawl into your mother's womb, for Jesus also said you must be born again". Am I in error here? Did Jesus not say "Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God"? (John 3:3, emphasis mine). And yet, not only is this a spiritual teaching, but this same passage shows someone (Nicodemus) interpreting it literally, and being mocked for it, by none other than Christ Himself.
By contrast, there are no examples in Scripture of people taking Jesus' words "this is my body" literally. This could be because Nicodemus' literal interpretation of "be born again" is somewhat anomalous. Jesus said all sorts of other things that are clearly not literal, and no one, barring those who sought to trap Him (e.g. Mark 14:58), took them as such. He called Himself the door of the sheep (John 10:7), and also says He stands at the door and knocks (Revelation 3:20). He calls Himself the true vine (John 15:1) (which also rather hurts the "my flesh is true food" argument). He tells us we must be born again (John 3:3), and take up our cross (Matthew 16:24). He even said we must hate our families (Luke 14:26). All these things, and more, proceeded from Jesus' mouth, and yet our religion would be excessively strange if we took them literally.
Furthermore, there are some very literal things Jesus did say at the Last Supper. For example, concerning the wine, of which He said "this is my blood of the new covenant" (Matthew 26:28; Mark 14:24; Luke 22:20), He also said "But I say unto you, I will not drink henceforth of this fruit of the vine, until that day when I drink it new with you in my Father's kingdom." (Matthew 26:29, cf. Mark 14:25; Luke 22:18). Read that again. "I will not drink of this fruit of the vine". In other words, it's not literal blood, and certainly no Jewish mind (least of all Peter's) would ever have interpreted it as such. And if they did, this would have resulted in at least some pushback. The absence of any clarification that "this is my body", and "this is my blood" are literal is sufficient, on its own, to prove it isn't.
So, we have the fact that Jesus said many things that weren't literal. We have the fact that no law of language compels us to take "this is my body" as an exception. We have the fact that no one seems to have interpreted Him literally. We have the fact that Jews, especially, would have both interpreted Him metaphorically, and would have resisted Him if they had thought He was speaking literally. We have the complete absence of any clarification that this is literal. We have all that, and yet, we still have more. See, not only did Jesus not clarify "by the way, this is literal", but He also explained the real meaning: "...this do in remembrance of me." (Luke 22:19, emphasis mine).
Remembrance. We break the bread, and drink from the cup, in remembrance, not in cannibalism, of Jesus. Paul further clarifies this when he says "For as often as ye eat this bread, and drink this cup, ye do shew the Lord's death till he come." (1 Corinthians 11:26). It was never a literal thing. Rather, it is a tradition by which we remember the sacrifice Jesus actually made. And indeed, so powerful is this symbol that the Early Church, who fought against heresies such as Docetism, used it to show that yes, Jesus did, in fact, have a literal body. Ignatius of Antioch, for example, wrote, in his letter to the Smyrnians, "For he suffered all these things for our sakes, in order that we might be saved; and he truly suffered just as he truly raised himself— not, as certain unbelievers say, that he suffered in appearance only (...) They abstain from Eucharist and prayer because they refuse to acknowledge that the Eucharist is the flesh of our savior Jesus Christ, which suffered for our sins and which the Father by his goodness raised up."
Ironically, Catholics love to cite that last quote (as if citing the Church "Fathers" is any kind of trump card against scripture) to say that, since Ignatius of Antioch believed in Transubstantiation, so should we. Yet, what we see with the addition of the words from chapter 2 (i.e. checking the context, as we ought to do), as well as his follow up comments in chapter 7, is that he isn't condemning the rejection of the literal Eucharist, but rather, the rejection of what it stands for! He's not saying "these people are in error because they don't think the bread is Jesus' body", but "these people are in error because they don't think Jesus even had a body!"
At this point, a Catholic might object, saying that Ignatius' words only make sense if the Eucharist does involve the literal consumption of Christ's body. In reality, however, it makes perfect sense, simply because this very powerful symbol requires a corresponding reality. You cannot have bread representing Christ's broken body if Christ had no body to break! You cannot drink wine in remembrance of Christ's blood, spilled for us, if indeed Christ had no blood to spill. And so it is, as Paul says, proclaiming Christ's death until He comes!
And so I will never understand the insistence of taking "this is my body" literally. We have no reasons to take it literally, and many reasons not to. We even have comparable scenarios in English! See the header image, in which I hold a picture of me in college. I say "this is my body", yet is it my body? Certainly not! It is a photographic representation of my body. Yet, it is entirely legitimate to say "this is my body", or even "this is me". It has never been necessary to take "this is..." literally! The bread and wine we consume are just that: Bread and wine, taken in remembrance of the Lord.