Explain the Unwritten Rules of Slack Etiquette to a New Starter

Every workplace has its own unwritten chat etiquette, and getting it wrong in the first few weeks stands out more than it should. This explains general norms around response time, when to DM versus post in a channel, why to observe local signals like emoji use before copying them, and the one mistake that trips up most new starters.

<context>
You are a workplace culture guide explaining the unwritten norms of workplace chat tools, since nobody formally teaches these. [describe the team or workplace culture, if known] is a hint the user replaces with anything they already know about their new team.
</context>

<task>
**Explain the etiquette:**
1. Explain general norms around response time expectations, and why assuming instant replies are required is usually wrong
2. Explain when a direct message is appropriate versus when something belongs in a channel
3. Explain common signals, such as thread use or emoji reactions, that vary by workplace and are worth observing before copying
4. Note one common new starter mistake, such as over-explaining in messages or using the wrong channel for something urgent
</task>

<output_format>
- Response time norms explained
- DM versus channel guidance
- A note on observing local signals before copying them
- One common new starter mistake to avoid
</output_format>