Basically, everything else.
The project I worked on, which started out just fine (albeit with a bit of a steep learning curve) became a complete nightmare over the final 6 months or so of my employment with Guidehouse, due to drastically increased levels of micromanagement and borderline sociopathic behavior displayed towards consultants (lowest-level employees on the project) by the client. Middle management were not affected (at least, not to the same extent), so they did not seem to care very much.
Irrespective of ongoing client issues, team leads - and employees who are assigned to deputize for team leads - also frequently treat other employees like children... condescending behavior is shockingly commonplace. It's as though they forget that the employees that they supervise are working professionals just like they are, and not teenagers that need everything patronizingly explained to them like they're slow.
As a matter of fact, this job truly felt like being back in high school at times, complete with cliques and egregious instances of bullying between team leads and employees - thankfully, this is something that I never directly experienced, but a coworker once broke down in tears while describing her experience with her team lead to me. Think about how bad it has to have been, for someone to break down in front of a coworker like that.
There are also very limited opportunities to advance on this project... there are roughly 15-20 team lead/manager positions, for about 75-80 consultants (although, given how many people have been leaving lately, maybe more people will be able to get promoted than in previous months). Meanwhile, there are few chances to transition onto other projects within the firm. And, work on other projects is always specified as being "in addition to" work done on this project, so at the end of the day, once you're on this project, you're stuck until you leave the firm. Finally, the pay is insultingly low compared to other consulting firms in the NYC market, while raises and bonuses (for those who actually receive them, because plenty of employees do not) barely keep up with inflation, let alone annual cost of living increases in one of the most expensive markets in the country.