Ah, thats not healthy nor is it helpful, a Goalie "obsessing over goals", pucks that got by. Not unless he's got a weakness, low stick side, low glove side, top shelf left or 5 hole or whatever. Then it would be a concern & corrected at the very next practice. If he's got a weakness like that however, prolly wouldnt have gotten past double or single A hockey. Cant be "obsessing over goals". Shake them off. And no, you dont "just accept that some will get by".
Strive for perfection..... perhaps some find that "obsessive" however the psychological aspects of playing the position & successfully in terms of technique, self confidence etc cannot be understated. You wont last long you obsess over goals, cant correct your technical & or mental errors, preparedness. Sometimes its something as simple as a blind spot, mask aint right, that sort of thing.... others, guys just a weak minded sieve. Uh? You go in there thinking, projecting... "no, your not scoring on me tonight, not ever Meatstick". Goals are scored if youve got a good Goalie as the result of a series of mistakes, breakdowns, failure to execute.