Growing pains - I've been with the company less than 3 years so I haven't seen a huge culture shift, but I've heard people that have been here longer than me say that the job was more fun when it was a smaller company. We had a big layoff (~5% of the workforce) earlier this year and I think it had a pretty big effect on the general mood and spirit of the company, but my department wasn't really impacted and I think people are less stressed than they used to be.
Focus on profitability - As a stockholder, I am all for this. As an employee, it's hard to see budget cuts when a lot of teams seem understaffed. We're still growing and hiring new people, but I'm hoping that the budget will loosen a bit once we reach profitability.
Reorganization - I have seen more department and team reorgs in the past few years than any other company. It can be pretty annoying, but most of the time they seem like thoughtful changes to improve the company and people seem to adapt pretty well.
Too much opportunity - This obviously sounds like a good thing, but it actually makes it difficult to prioritize and focus when there are so many business and growth opportunities.