Is it thought of as dangerous to leave a hernia as is?

Yes, if you have: Any pain or discomfort. It can incarcerate or stangulate, which means intestine or other organs can get entrapped and die. Also, it will gradually get bigger and cosmetically unacceptable.

Asymptomatic Hernia: If it is not causing any symptoms than generally it is ok to observe generally best to be evaluated by a surgeon so that they can help guide your decision.

Depends: This depends on the size and location of the hernia, and the problems it's causing. There are 3 reasons to fix it - symptom relief, preventing it from getting worse, or both. Use your common sense to assess the risks and benefits of observation vs. Operation. You will make right decision.