The title may be a bit misleading, but I've hit a point in my game that, while I'll still attempt to complete as many as possible, I have become willing to accept failure and simply move through the game. My very first failure was back on sequence 8, during the chase sequence post eavesdropping. The objective was to not push aside anyone while you chase your target. I tried time and time again, until I finally figured I'd just try to head him off instead of chasing directly. I was in front of him, and either I nudged him or he barreled in to me just a hair before a cutscene commenced.
He was apparently considered a member of the crowds, the cutscene started immediately after and set a checkpoint, and I was going to be damned if I had any intention of immediately restarting that entire memory.
Has anyone else hit a point like this in their game, where they are more or less screwed by the checkpointing and thus give up on obsessively and immediately completing optional objectives?