Let's start with a classic:
f = (1/2π) * √(k/m),
where k = kindness, m = the mass of your smile.
Need a little more frequency in your life?
R = C2 × (Time ∞),
where C = the chatter of cosmic cats.
And if you're feeling particularly resonant:
λ = d/A,
where d = dreams and A = awkward giggles.