  This paper contains three observations on commutators of Singular Integral
Operators with BMO functions:
  1) The subgaussian local decay for the commutator, namely
\[\frac{1}{|Q|}\left|\left\{x\in Q\, : \,
|[b,T](f\chi_Q)(x)|>M^2f(x)t\right\}\right|\leq c e^{-\sqrt{ct\|b\|_{BMO}}} \]
is sharp, that is, it is subgaussian and not better.
  2) It is not possible to obtain a pointwise control of the commutator by a
finite sum of sparse operators defined with $L\log L$ averages.
  3) If $w\in A_p\setminus A_1$ then $\left\|
wM\left(\frac{f}{w}\right)\right\|_{L^1(\mathbb{R}^n)\rightarrow
L^{1,\infty}(\mathbb{R}^n)}=\infty$.
