I want to develop the lore of my world for a project. The main idea is: The protagonist has something (can be a curse, whatever, it will be decided later) that makes everyone forget about him when he is not around.
Explaining a little better: If he/she is with someone, all is fine, but when he/she gets more than a certain distance from that person, that person's memory about the protagonist will start to fade away, until that person completely forgets. What would be the implications of such world for the life/personality of the protagonist? Also, I was thinking about problems, like he/she buys something, and the seller would forget about it, so he/she needs to make sure no one thinks it's stealing.
EDIT: Answering all the questions (I was with a 12-hour shift from work, sorry guys).
It wouldn't strike at birth, should be something it was acquired later on by the protagonist, maybe on his/hers early 20s. As given on comments, it would be very interesting to have some antagonist with the same situation, but maybe with a better grasp/control of it, or at least knowing how to greatly use on his (the antagonist) favor.
Once you get out of radius, it would slowly fade way, and yes, depending on your relationship with the protagonist, the memories would take longer and harder to forget. The shopkeeper you just bought something would quickly forget, but some kind of lover would take way more, like days/months, but would start forgetting one fact at time. Memories lost this way, so far, would not come back, but I'm still thinking about it.
Documents, things destroyed and on would stay the same. So if the protagonist is punched or punches someone, it would still be there even if the person forgot what happened, and pictures taken this way would still keep his/her record (but people who see will get that feeling of "how the f*ck this guy got in my picture?"). So, to make it clear, any physical/digital record made would be kept.
I was wondering about the time setting be placed somewhere with not advanced technology, like medieval/steampunk time, so people would be more dependant of what is told to them, also trips would take longer, making the condition of the protagonist worse (a trip that we would make in 2hr by plane would most probably take 1 full day by horse, leaving time to some people to forget him/her). So, even with his/her SO, things could be complicated, like, the SO remembers being with someone, but can't remember who.
So, if the time setting is indeed the one I stated, jobs as a mercenary would fit well, if set in the modern age, remote jobs would do just fine, as the comments pointed out.