The document discusses 50 things that software teams should avoid doing related to architecture, code design, testability, documentation, team maturity and process. Some examples include treating a monolith as inherently bad, using microservices as an escape plan from technical debt, dogmatically using design patterns, insufficient test coverage, messy source control history, developers working in isolation, artificial sprint goals, and long-running stand-ups. The document is written by Dennis Doomen, an architect with 25 years of experience in the .NET space.