Recruiters often recommend to "reiterate your enthusiasm for the job for which you have applied" in the interview. However it may be unnecessary or inappropriate...
Is it professional to demonstrate enthusiasm in the job interview?
Update: surprisingly most readers and high-ranked editors who labelled this question as "unclear" transform this question to something else in their heads. Please stay on topic and try to answer exactly what is asked. Try to think what would be expected from you and whether would you attempt to "demonstrate enthusiasm" without fear of spoiling your professional impression (and why).
This question is not about definition of "enthusiasm" (Workplace is full of unspoken rules). This question is not about how to express enthusiasm or how expression of enthusiasm affects chances to be hired. This is not a question whom you prefer to hire or how you prefer to interview them. Do not assume incompetence or lack of care for work although you can assume that "enthusiasm" is not part of the job description. This is not about particular interview but generally about expressing enthusiasm by experienced professionals who already dedicated significant part of their life to their area of expertise. This question is just about impact that expression of "enthusiasm" (whatever it is) may have on perception of professionalism.
Please note that situation is not about hiring non-profit (e.g. charity) employee or a partner (where organisation's goal can match candidate's passion). This is about situation when hired labour may be genuinely passionate about work or may be pursuing "paying the bills" goal.