Poor communication from management to lower-level employees. Low pay and they expect you to keep utilization up, even when there is no client work. Promotions and bonuses are dependent on billabilty. Taking care of the necessary work that is not billable is expected to be done for free on your own time. Tech and temporary employees are sometimes viewed as incapable of anything other than following SOPs, and their work is consistently devalued. I've overheard project managers bad-mouth employees in front of everyone but the employee, and they rarely put the work in to communicate to those employees their expectations or concerns. If a manager has a problem with you, you'll never know unless you overhear them bad-mouthing you, by that point they've already made up their mind about you and your capabilities. Some will act petty, doing things like giving you the silent treatment.
Some managers seem over-burdened with their work load, and will put off even the simplest replies to emails because they're so busy.
Some managers seem threatened by new ideas, or questions about the way things are done. Some PMs are territorial over work, and discourage employees who express interest in acquiring new skills. There is little investment in training.
Certain managers are blatantly sexist, telling female employees to "smile" and making fun of employees in front of others about how some female employees will "never get a boyfriend." Other examples are subtle, sometimes it happens in the hiring process, and I've never felt comfortable going to HR with my concerns.
Despite the company having a great D&I team in place, they really could be a more diverse environment.
Lastly, there are few opportunities for advancement, especially if you're at the tech level.