- Promise a new feature to a customer without running it past your team.
- Generalize your first three customer interviews into a market segment.
- Confuse sales calls with customer learning/research
- Believe your own marketing/selling materials about why customers use and love your product
- Announce that you’re "CEO of the product"
- Tell engineers how to solve a technical problem
- Postpone meeting your internal counterparts
- Confuse process steps (stories, tickets, releases) with market success (renewals, revenue, customer love)
Also take a look at 'What a Product Manager does on the first day / week / month / quarter in their new role' - a session that we have run at the Cambridge Product Management Network a couple of times.