In a nutshell, it was a big thank-you to Hashem for bread.
Rav Miller notes that nowadays, bread and other products (like pizza & cakes) are so plentiful and cheap, it's very hard to appreciate the value of plain old bread.
People used to eat a piece of bread and then save the rest for the kids.
But they were grateful for that one piece.
It reminds me of a Sephardi-Yerushalmi woman I met who recalled the old days of Yerushalayim from around 60 years ago.
She described what people ate throughout the day, which was very simple — yet satisfying.
Like ONE piece of bread in the morning, with a bit of cheese, and a bit of cucumber-tomato salad — and not everyone enjoyed even that much, either.
A Leil Shabbat meal consisted of one piece of challah, a piece of fish, and piece of chicken or shnitzel, plus kugel.
That was it, more or less.
The Shabbat day meal was cholent — and maybe some kugel.
"And we were full!" she insisted. "We weren't hungry!"
She went on to say what she'd heard from others: The food had more bracha in it back then.
Because of the bracha in the food, it was naturally more satiating.
She and others in that class referred to the lack of Shemitah-observance and Shabbat-observance that increased since then, and claimed they'd heard these desecrations had decreased the bracha in the food, making it less satiating.
I'm honestly not sure if Shemitah and Shabbat are the reasons because there were problems with Shemitah and Shabbat back in the Fifties too.
But maybe it was still better back then. Certainly, prior to the Fifties and going back to the late 1800s, religious Jewish farmers carried out mind-boggling sacrifices to keep Shemitah.
Yet maybe it was more than that.
Maybe it was because they appreciated whatever they managed to have.
Maybe that gratitude imbued the food with more bracha.
Yes. Maybe they were grateful.
Looking at Our Relationship with Hashem from the Right Angle
Rav Miller quotes the Gemara, which tells us this Tehillim is singled out as the Hallel Gadol/The Great Hallel.
Because it's full of praise & gratitude to Hashem. It reminds us of all the wonderful things Hashem has done and continues to do for us.
And that, says Rav Miller, is really what the Omer is all about:
"...one day of gratitude, two days of gratitude, three days — that is our preparation for Kabolas Hatorah [Receiving the Torah]."
This is a type of spiritual immaturity that needs to be dealt with and, of course, I've been working through this too myself over the past several years (and flailing against the all-encompassing entitlement culture of America in which I was raised).
In reality, we owe Hashem.
Even if we've suffered a lot, we still owe Him for the revealed good He has given us and we even owe Him for the suffering too because the suffering is what atones us into a blissful Eternal Life when the times comes at 120.
There is so much we desire (whether it's irrelevant or even bad things, or whether it's truly good and spiritual ideals) and there's so much we are denied, it's hard to focus on what we DO have and also keep in mind that whatever we feel we lack is davka the challenge that leads to our ultimate good.
Though I've improved in this area, I still struggle with this too.
But Rav Miller recalls the famous scene of the Roman gentile who came to Shammai and then Hillel, requesting to be taught the entire Torah while standing on one foot.
Shammai rejected him, but Hillel told him: "What is hateful to you, don't do to your friend."
Then Rav Miller goes according to Rashi's first interpretation of this and says that your "friend" mentioned by Hillel is actually your Friend with a capital "F": Hashem.
It's like what Rav Levi Yitzchak Bender always said: Talk to Hashem like He's your Best Friend, who's always Compassionate & Forgiving and can do anything for you.
And when you really look at everything Hashem has done for you, says Rav Miller, you can't help but to ask the question David Hamelech asked in Tehillim 116:12:
“Mah ashiv laHashem, kol tagmulohi alai – What can I pay back to Hashem for all that He does for me?”