The greatest problem I think as a junior is that people who are new or inexperienced with SE do not know how to accept an answer and are not aware of the site's features. They just come across the site thinking of it as a Q/A site where any question is answered straightaway without credit. The reason is that many skim over the introduction just to earn the INFORMED badge.
Secondly, many new contributors and even old ones cannot properly phrase or convey their question. The answers they receive are relevant and fine but they personally donot feel that the answer is correct. The Comment section is a testament to this. Many contributors stray from the topic of their question in the comments despite the answer being perfect.
Thirdly, the site comprises of contributors from PhD scholars to those who are just Lower Secondary students. Thus many contributors receive answers that are far too complex for them. For example this contributor received a complex answer according to his level of study so he reposted his question despite the answer being well explained.
Common Ion Effect Equilibrium