It indicates that you have been working. To do a lab really well, have your report done well in advance. If you can't get the answer in the usual manner, start at the answer and derive the question. In case of doubt, make it sound convincing. Team work is essential, it allows you to blame someone else.
All unmarked beakers contain fast-acting, extremely toxic poisons.
No experiment is a complete failure. At least it can serve as a negative example. Any delicate and expensive piece of glassware will break before any use can be made of it. Chemists do it reactively. Chemists do it in test tubes.