What are the biggest mistakes with beginner tips in Grok?

For What are the biggest mistakes with beginner tips in Grok?, I would separate the problem into setup, output quality and repeatability. beginner and tips fits into that because it can change the result quite a lot depending on the workflow. The original point — "I have a question about Grok that may be useful for other people working with it too. I am particularly interested in beginner tips and data quality. I would like to compare appro…" — gives a useful starting point for that comparison.