> You can always just exit the program.

Or never start to use it in the first place.

The fundamental problem with Slack is that its interactions are not structure in the right way to be useful in non-real-time. An email thread has two critical pieces of structure that Slack threads lack: a subject line, and a beginning. With email, it's easy to tell where a particular discussion started, and which messages have to do with that discussion. On Slack, these things are all intertwingled. In order to find the beginning of a discussion you have to scan everything in the channel. That is what makes Slack a distraction. It's much harder (like virtually impossible) to filter content by topic after the fact.