The biggest red flag is the nepotism and favouritism that riots the office spaces. If the people at the top do not like you, you can forget about any sort of growth - and they can choose not to like you simply because you stood up for yourself (or someone else) in a sticky situation or because you challenged their 10-hour workdays (yes, 10 hours, while also working through your lunch break and while many employees travel from really far too, with no reimbursement on their travel). However, if they do like you, you can expect a lot of promotions, salary increments, performance/achievement related bonuses, awards and an "exclusive in" with their personal friend groups. Heights of absolute clique-ism - which makes you feel like you're in high school all over again!
Second, there is pretty high attrition rate within the company, save for a few top guns mentioned above who have been around since the company was birthed. With more new people coming in, internal growth for an employee is killed imminently - they would rather hire someone at a higher position than promote a hardworker internally - and the disgruntled employee ends up having to train the new hires, which kills their spirit. The attrition also means that not everyone gets replaced, thus resulting in heavier workloads for the rest of the team, which obviously does not get adequately recognised neither through promotion nor remuneration.
Third, managers face so much pressure from the top which trickle down onto their teams, that their empathy ends up at an all time nil. Several incidents include how some team members have had to take emergency leaves (think along the lines of accidents, sudden hospitalisation, family emergencies etc) and the managers have reached out to them for work related concerns, while making little to no efforts to understand the state of mind of the team member.