I enjoy working with patients, sometimes I get to work with one who's particularly fun to work with and pokes fun at their own conditions or just cracks a joke.
It always breaks my heart that I need to double check if I can joke back or be laid-back towards the patient, after all – I may be considered “unprofessional” by my higher-ups if I do.
It just makes me sad how fun human interaction is considered unprofessional.