To be fair Dave, I think the biggest concern is that each negative result that we seem to somehow snatch from the jaws of victory will gradually and terminally erode the confidence of the players. There is already a palpable change in mentality when we go ahead and it's a difficult thing to reverse. Players are a fickle bunch and will look around them for someone to blame which often leads to a manager "losing the dressing room". We can't keep blaming bad decisions, they happen to every team, but the trend of throwing away games could well spiral out of Martinez' control at this rate.
Martinez has a big job on his hands. If we can go on a good run before the end of the season and give us even a glimpse of our real potential, a lot of people would be happy for him to stay. But if results don't improve, I think people will be right to question his ability after 2 years which is, bafflingly, a long time in modern footballing terms. He still unreservedly has my vote, but I can't say I blame people for starting to look elsewhere.