[ploxiln]

My bash always starts near instantaneously, because I have never tolerated it not doing so.

bash-completion (available in many package managers) used to be one culprit, should be less of one now due to on-demand completion loading, but still noticeable. I don't use it. Another is rvm, nvm, etc (managers of ruby or nodejs versions for development, install process typically adds to your .bashrc).