Adapt Your Design Thinking
Your design thinking should evolve depending on where and when you commence a project. Sometimes you join a company or team when they are already in the design or development phase, and you may feel the urge to double-check or validate certain things. It's important to have a voice. But also be mindful of decisions you disagree with, especially if some of them have already been validated by data.
I've learned that not everyone you come across has an agile or lean mentality. Often people may have robust thought processes. Be patient, lend a helping hand wherever you can, and adapt your design process accordingly.