While we're thankful for its existence and we delight in its indulgence, the ice cream sundae wasn't always a thing. As hard as it is to imagine, there was a time when people had to live their lives without them. Luckily this isn't the case anymore, and we have soda to thank for it. Well, not just soda, but the Blue Laws (which restrict activity on Sunday) and soda jerks as well.
In the 1880s it was prohibited to sell ice cream sodas on Sunday in some parts of the country. To not miss out on a whole day of business, soda jerks came up with the sundae which was essentially just an ice cream soda (ice cream, chocolate sauce and soda) without the soda. And hence, the invention of the sundae (named after the day of the week when it was sold).
Now that you know, you should celebrate -- with a sundae.