Whats the one productivity tool you cannot live without? And whats your occupation?

I'm a Product manager and I can't live without Trello. It's very simple, yet helps me plan a lot. What's your tool, @benedikt_fb?:)

I'd say, GanttPRO https://ganttpro.com/ is the tool I can't live without. This online Gantt chart maker helps our marketing department and the entire company to: - Visualize project timelines. - Collaborate with team members. - Track progress. - Identify bottlenecks. - Manage resources. - Boost productivity in general.