It is awkward to get your head around things when a less than perfect finish is required. Working on a pub in Newcastle some years back and the internal finish was ‘distressed brickwork’, lay the brick, tap it to the line but leave the ‘snobs’ on the bed and perp. Very unnatural to leave them and not scrape them off with your trowel, there were many bricks relaid at first due to absentmindedly carrying out the habit of a lifetime.