Have a look at this report.
Selling vanilla is good. Really good.
Adding fancy toppings is nice as well. It'll probably get you higher revenues in the long run. And making fancy toppings is very cool.
But if the kid has a cut in his pocket-money, here's the thing - he'll still eat ice-cream.
It'll be plain vanilla without the toppings though.
And can your business adjust for this?