its what you tell your friends when you have to go poop
poop time

ti;dr means, Too ignorant, don't reply. It was spawned when the number of illiterate fags proliferated on the internet. In other words, it is the anti tl;dr.

op-ti-rec-tum-it-us, noun,

1. An ambiguious mental condition which manifests itself by outbursts of negative thinking and behaviours. Experts have hypothesized that the condition peaks whenever neuro-transmitters from the optic nerve cross the path traveled by transmitters from the nerves of the anus or other rectal areas. The most commonly observed symptom is an obvious disposition by the sufferer that includes a severely excremental outlook (shitty-outlook) on life and living.

2. Negative thinking; hopelessness.