Is Torah a Burden or a Gift?

Avot 3:9

The Torah doesn't say that the Torah was given on Shavuot and according to Rebbi Yossi it wasn't given on Shavuot, it was given on the seventh of Sivan! Why do we call it זמן מתן תורתינו. Further, even if the Torah was given on Sivan 6, it was broken (on the 17th of Tammuz)  before we ever received it - we received the Torah on Yom Kippur!

In Bechukotai we are warned to keep the Torah by toiling in it (see Rashi to Vayikra 26:3); in Ki Tavo we are warned that we will be punished for not keeping the Torah joyously - which is it?

Delivered at the OU Israel Center, June 3rd, 2019, 29 Iyyar 5779