Another reason you should wear mask and take other precautions, even if you are healthy, still you may get virus but it will not harm you, you will become positive and after few days due to your immunity you will become negative.
All these happen without any symptom, even you will not notice it's happening...
But during this period of +ve to -ve, you are a carrier... It can be transmitted from you to old or weak immunity people, their life become danger...