We survey some classical norm inequalities of Hardy, Kallman, Kato, Kolmogorov, Landau, Littlewood, and Rota of the type, and recall that under exceedingly stronger hypotheses on the operator A and/or the Banach space X , the optimal constant C in these inequalities diminishes from 4 (e.g., when A is the generator of a C 0 contraction semigroup on a Banach space X ) all the way down to 1 (e.g., when A is a symmetric operator on a Hilbert space H).We also survey some results in connection with an extension of the Hardy-Littlewood inequality involving quadratic forms as initiated by Everitt.