"And when the children of Israel saw it, they said one to another, It is manna: for they wist (knew) not what it was. And Moses said unto them, This is the bread which the Lord hath given you to eat." (Exodus 16:15, emphasis mine)
"Because they believed not in God, and trusted not in His salvation: Though He had commanded the clouds from above, and opened the doors of Heaven, And had rained down manna upon them to eat, and had given them of the corn of Heaven. Man did eat angels' food: He sent them meat to the full." (Psalm 78:22-25)
So, "manna" is essentially Hebrew for "what-ness". That's what the children of Israel called it. They had no idea what it was and they named it as such. Like a permanent state of wonder tinged with stupefaction. And they left it at that. The passage from the Psalms is expressing a similar sentiment aimed at the failure on the part of the Israelites to then show commensurate gratitude in the face of such a wonderful and stupefying miracle. And before I go any further, dispense with the idea that the manna was a naturally occurring plant-based food (as is commonly believed among secular historians and anthropologists). Werner Keller, in his book The Bible as History says that the manna was actually from a shrub that grew in abundance in the desert. While his book is good for substantiating the historicity of much of what happened in the Bible, he applies the same skeptical, dispassionate eye to everything, giving perfectly rational, non-spiritual explanations for the supernal and supernatural.
"Every good gift and every perfect gift is from above, and cometh down from the Father of lights, with whom is no variableness, neither shadow of turning." (James 1:17)
I find this to be a struggle sometimes. And it's all contingent on the level of gratitude and fellowship that I express to God. Think about the things in your life that you know to be from Him. Are they anything out of the ordinary? Sure, you have a job that pays the bills and a family that has grown and developed over the years. These things are necessary and integral to your life. God's gifts are large and small. And you can look back and see in hindsight and retrospect, the hand of God weaving things in and out and making up the tapestry that is your present life. If you don't mind then, let's pull out a thread and inspect it (don't worry, God will weave it back in). What is it? It's a gift that can be traced directly back to God's hand. But that's if you choose to look at it as such. When we endeavor to see our life and its infinite threads as saturated with God's presence and principles we will necessarily run up against this idea of unbelief: things just happen. This attitude of unbelieving pragmatism, that things just happen with no supernatural agency does indeed look appealing at times. As if it isn't God (or a "god") who does anything. I'll explain: There's a fine line (I think) between an over-reliance on science, with its attendant benefits and blessings, and a superstitious and irrational belief that "everything happens for a reason". That each little incident has its impetus in the spiritual. Admittedly, I can be a little paranoid at times but where's the happy medium? Is God omnipresent? This isn't panentheism. I'm talking about the Holy Spirit. Because if you apply yourself to either end of the spectrum out of His leading, you'll end in missing God altogether.
And here's the other end of the spectrum.
"Manna", not to be confused with "mana". There's a correlation here. Apart from being a homophone, "mana" (with one 'n') comes from the Pacific islands and has its root in archaic superstition. It isn't really a "thing". The 'mana' is a supernatural force that is believed to be inherent in everything. Reason I bring this up, apart the fact that they're homophones (and antonyms, almost), is because, while I may not believe in a supernatural 'essence' that is neutral and dwells within inanimate objects, the Bible does record instances where articles of clothing were imbued with, not an impersonal force, but the actual power of God.
"And God wrought special miracles by the hands of Paul: So that from his body were brought unto the sick handkerchiefs or aprons, and the diseases departed from them, and the evil spirits went out of them." (Acts 19:11)
That's amazing. What was it that could have caused Paul to be so full of the Holy Spirit that the very presence of God was transmitted from him to the clothes that he wore and the cloths that he came into contact with? I'd venture to say that he cared more for God than all else. When you walk with God, thanking him for the everyday occurences that anyone could pass off as chance and happenstance, God will sit up and take notice. Your faith will be rewarded and He'll help you see his hand in things. Because it's there. There are deeper levels to existence that we're not privy to if we're in doubt and unbelief.
We don't believe for nothing. And we don't believe in nothing. God is very real. It's the attitude of the heart that will tell whether or not we see Him in this life. And if you have questions after that, God will answer them for you, in His time.