Be Happy; Do Mitzvot
There are many mitzvot that "depend upon the Land" - Mitzvot Ha'T'luyot Ba'Aretz. Bikurim is one of them. But Bikurim is unique among these mitzvot because of a second mitzva attached to the mitzva to bring Bikurim, as commanded in Parshat Mishpatim (and repeated in Ki Tisa). And that is the Bikurim Declaration. It is acombination of a quick review of the Egyptian experience, the gestation period of the Nation, and a statement of one's thankfulness to G-d for living in Eretz Yisrael and enjoying its blessings.

The Torah follows the text of the Bikurim Declaration with the "command" to be happy, to rejoice in all the good that G-d has given you and your household.

Later in the sedra, in the midst of the Tochacha, the Torah prophesies and warns against not serving G-d with happiness — specifically when we enjoy "all the good" (as referred to in the Bikurim Declaration). D'varim 28:47 can be seen as specific to this "all the good" connection, or it can be generalized as an admonition for not serving G-d, doing mitzvot, living in Eretz Yisrael... being Jewish, with "joy and a glad heart".

You keep the Shabbat, but is it a burden, a "take it or leave it" situation, or are you thrilled and delighted to be a Shomer Shabbat.

Do you ever well up with tears of joy at living in Eretz Yisrael? Are you ever moved to joyfully say (or think) ASHRECHA YISRAEL, MI CHAMOCHA - Happy are you Israel! Who is like you?

Sure, we have problems... but that should not prevent us from serving G-d with happiness and joyfully thanking Him for the good that we have. We can pray to G-d to reverse the bad parts of our situations, but that should not prevent us from expressing our gratitude to Him for the good which we enjoy.

If rejoicing is "commanded" in the context of the "fruit of the Land", then we should rejoice and thank G-d for:

Availability of Shmita-okay flowers for Shabbat and Yom Tov;
Taxi & bus drivers (even non-religious ones) who wish you Shabbat Shalom, Shavua Tov, Chag Samei'ach and Shana Tova;
Signs in buses asking you to give seats to the elderly by quoting Vayikra 19:32;

These too are fruits of the Land.

How much more so must we be joyous and thankful for Torah & Mitzvot, Israel, and "simply" being Jewish.