  We present the number densities and physical properties of the bright
galaxies spectroscopically confirmed at $z\sim7-14$. Our sample is composed of
53 galaxies at $z_\mathrm{spec}\sim7-14$, including recently-confirmed galaxies
at $z_\mathrm{spec}=12.34-14.32$ with JWST, as well as new confirmations at
$z_\mathrm{spec}=6.583-7.643$ with $-24< M_\mathrm{UV}< -21$ mag using ALMA and
Keck. Our JWST/NIRSpec observations have also revealed that very bright galaxy
candidates at $z\sim10-13$ identified from ground-based telescope images before
JWST are passive galaxies at $z\sim3-4$, emphasizing the necessity of strict
screening and spectroscopy in the selection of the brightest galaxies at
$z>10$. The UV luminosity functions derived from these spectroscopic results
are consistent with a double power-law function, showing tensions with
theoretical models at the bright end. To understand the origin of the
overabundance of bright galaxies, we investigate their morphologies using
JWST/NIRCam high-resolution images obtained in various surveys including PRIMER
and COSMOS-Web. We find that $\sim70\%$ of the bright galaxies at $z\sim7$
exhibit clumpy morphologies with multiple sub-components, suggesting
merger-induced starburst activity, which is consistent with SED fitting results
showing bursty star formation histories. At $z\gtrsim10$, bright galaxies are
classified into two types of galaxies; extended ones with weak high-ionization
emission lines, and compact ones with strong high-ionization lines including
NIV]$\lambda$1486, indicating that at least two different processes (e.g.,
merger-induced starburst and compact star formation/AGN) are shaping the
physical properties of the brightest galaxies at $z\gtrsim10$ and are
responsible for their overabundance.
