I just know Bruce is extremely pety when it comes to pranks or to just actions that he despises.
I feel it deep in my bones that whenever someone tries to prank him or to make him do something he does not want to do he makes their life's 100 times worse just for the sick of it.
Once Alfred feeling smart decided to put a food that he hates blended into a safe food and only told him(very smugly) after he finished eating.
After a whole month of the incident Bruce enters the kitchen and gives Alfred this huge smile and just says "I've spend a month putting a amount of frog eggs into your tea on random days of the month,try guessing which days the tea tasted different" and just left the house for the entire day
Alfred panicked for hours because FROG EGGS??AND HE DIDN'T TASTE IT??(Plot twist:it was all the tea's,every single one of them)
Alfred quickly learned never to mess with Bruce,it was just easier to make quick jokes that must annoy him than mess with the things the boy enjoyed
So when Bruce came back from patrol with a murderous look on his face,his good old butler new someone was going to suffer extra hard the next few days.
And well,he is in fact loyal to his ward,and Alfred as always taught to follow the side that would win in the end.
