I have seen personal/friendly relationships at work between QA and development, product management teams hurt product quality. How? The QA team members cover up any product quality risks for fear of damaging a work relationship.
The reason is that these relationships may, at times, introduce compromise and risk of product features and as a QA person.
Your responsibility is to the product and customer experience, not to make friends or protect future job references.
Be careful to manage your rapport with co-workers because, as a QA professional, you must ALWAYS represent the customer and expose and risk (process, design, etc) that has potential to be negative in any way.