Have you ever found yourself concentrating so hard on the task at hand that, when a soft voice suddenly says 'Madam?' near you, you JUMP out of your skin, so to speak?
Lets say you are reading, or walking, thinking of something or the other, or cleaning your clothes cupboard, colouring with crayons, whatever, somewhat of a quiet activity, and intentionally or unintentionally someone comes up to you and calls you.
(a) Have very good peripheral vision and can detect them a mile off and while you do have your head bowed down to the task, are not unduly surprised and look up, affixing a polite smile
(b) Give a leap, spill the glue, scatter the crayons, clutch at your beating heart, exclaim in a very unladylike snort, spill the drink, drop the clothes, and generally give them a big laugh
(and then after they laugh and go away and five minutes later they come back and do the same thing again, this time surely intentionally, do you get angry at their amusement?)
In this house which has so many dark corners, in fact, so many corners and turns to get from here to there, a hundred places for a small creature to hide herself in (if she can control the giggling), its a wonder I have not had a heart attack yet.