The fact that two balls charged with 1 coulomb each would repel/attract each other from a distance of 1 metre with a force sufficient to lift the Seawise Giant would suggest me otherwise, but has anyone ever charged an object with 1 coulomb of net charge?
Why was such a ridiculously large charge chosen as the unit of charge? Or better, why did we give the Coulomb constant such a big value instead of using a value in the same order of magnitude of the Newton constant ($10^{-11}$)?
EDIT
For the historical reasons that explain why the coulomb was chosen as the unit of charge please refer to the good answers given to this question.
After a bit of research I have found that the highest voltage ever created is $32\,\mathrm{MV}$ at the Oak Ridge National Laboratory. With such a voltage the best we can do is charging a copper sphere the size of a basketball with around 424 microcoulombs:
$$Q = 32 \times 10^6\,\mathrm{V} \times 4\pi\epsilon_0 \times 0.119\,\mathrm{m} = 4.237 \times 10^{-4}\,\mathrm{C}$$
Such a sphere, when placed at a distance of $1\,\mathrm{m}$ from the surface of a similarly charged sphere, would experience a repulsion of $1052\,\mathrm{N}$ (the force needed to lift $107\,\mathrm{kg}$).
If the maximum voltage we can access is $32\,\mathrm{MV}$ and we want to charge a sphere with $1\,\mathrm{C}$, all we need is a sphere $561.7\,\mathrm{m}$ in diameter. It might often snow on the top.
Best Answer
Actually the ampere (SI unit for electric current) was defined first (in 1881, see Wikipedia: Ampere - History). They chose this size for $1$ ampere, probably because at this time such a current could be produced with a decent electrochemical battery, and was easily measurable with a galvanometer by its magnetic effect.
The natural consequence of this is: A flowing charge of $1$ coulomb (i.e. a current of $1$ ampere flowing for $1$ second) is also a convenient unit, neither ridiculously large nor ridiculously small.
The fact, that a static charge of $1$ coulomb is a really big thing, is an entirely different story, which has to do with the large electric force between charges.