You don’t have to perfectly mesh with a new office on your first day. Adapting to a new company is a process: it’s important because you’ll be spending most of your day with these people, and you’re dependent on this employer to make sure that you have the money necessary to cover your bills. You don’t need to take in cookies for your new coworkers, but you do need to make a serious effort to adapt. It’s worth noting that not all companies will be a perfect fit for you. If you’re having trouble adjusting to a new employer, you should give it your best effort but also be willing to walk away if there’s no hope of it working. It’s better to do that during your orientation period, if you can.