$\mathrm{s}$ orbitals are spherically symmetric while $\mathrm{p}$ orbitals are not. For Boron, the electronic configuration is $\mathrm{1s^2 2s^2 2p^1}$.
In which p orbital does the most energetic electron lie? Is it $\mathrm{p}_x$, $\mathrm{p}_y$ or $\mathrm{p}_z$? Since all the three are degenerate, how does the electron decide which orbital to occupy? If it occupies any of the one orbitals, is a neutral atom not spherically symmetric? Or does the electron keep changing between $\mathrm{p}_x$, $\mathrm{p}$ and $\mathrm{p}_z$ rapidly (or in a superposition of occupying all the three orbitals at once with the probability of finding in any one of the orbitals equal to $1/3$)? The same question can be asked for $\mathrm{d}$ and $\mathrm{f}$ orbitals.
