Harming another life-form intentionally or not – this includes murder, deaths at war, accidents, killing animals for food or sport Religious rituals, especially sacrificial rituals Having strong pity for another life-form suffering or dying Invoking another life-form into you directly through rituals etc Giving away your awareness in any way Having judgements about entities Having a soul contract, agreement, vow, pledge etc that allows entities to interact with you
Some people are more susceptible to picking up stray spirits than others. There are many ways of unintentionally picking up spirits. Hospitals and pubs are very likely places.Hospitals, because people die in them, and therefore there are likely to be more lost souls in hospitals than in other places.