Regulations:
Large corps are much stricter regulated and this adds to your responsibilities to do boring stuff.
Permissions:
Large corps spending lots of resources for reinventing and improving systems of access controls and permissions as well as sets of exceptions to such systems.
Average worker age:
20+ something for startup, 40-50+ something for corps.
Accessibility of top management:
Startup: you knock the door and talk to the guy, Large corp: you send email to C*O of large corp and get no reply not because he is busy, but because his secretary pre-filtered emails and discarded yours.