"Can this much fluid really be contained in such a small human?"
"How many times a day can a toddler ask you for a cookie and expect the answer to change?"
"Will you ever feel not tired again?"
Then, of course, there are the factual questions... such as
"What do you do for a toddler with a stomach ache?"
In the last couple of years drug manufacturers have added Aspirin to pretty much all of the over the counter stomach drugs like Pepto which means they are no longer appropriate to be given to children.
This is exactly the problem we faced recently when a stomach bug made its way around our day care. Luckily for us, a Swiss friend of ours had given us a cute hot water bottle with sleeve as a "welcome baby" present (we were told this is a traditional baby gift in Switzerland). The brand of bottle we got cannot be easily purchased in the US but there are a number of similar, well-reviewed products like it are available on Amazon (Classic Rubber Hot Water Bottle w/ Cute Knit Cover and Children's Rubber Hot Water Bottle w/ Cute Knit Cover are two examples).
What's great about the bottle we have (and the ones I'm linking to) is that it's smaller than a full-size 2 liter bottle. The cute cover is fun for our toddler and is easier to keep on than just a towel. Of course, it also provides her with comfort. A hot water bottle is good for a stomach ache both because warmth can help relax a cramping stomach and also because it provides some measure of "doing something" placebo effect for the child.
I really recommend getting one of these because like a thermometer, diaper rash cream, saline solution, and other first aid staples, this is the kind of thing that's good to have in the house as a "just in case" (this is NOT a good time to head out to the drugstore and Amazon just can't deliver that fast). Because, of course, the ultimate question without an answer is
"When will my child be sick next?"