Some newer appliances will simply refuse to work though.
If colour didn't matter, because it's AC, there'd be no need for colour coding.
wrong.
the colours are there to ensure the protective device is in the Phase( line) (live) conductor not the neutral which should generally be at 0V . Most motors in fridges are universal AC/ DV so it doesn't matter which way round the polarity is they will still run the same way. Washing Machines are the same , the motor runs backwards by changing Rotor or Stator field.
Most modern appliances have a transformer and rectifier in them for the electronics. again not an issue with reverse polarity in respect of working.
for Safety ( and compliance) the Brown MUST go into the Load L terminal and the Blue MUST go into the Load N . this ensures if there is a fault the fuse operates correctly and in event of overcurrent doesn't leave the live energised and the N with voltage on at appliance. ( hurts - YCAMHIKT)
the yellow at the nottom is the Green and yellow CPC.( circuit Protective conductor) .
my guess is the house is built before 1977 as there is Green only sleeving on the fixed wiring and Thats when the regs changed to Grn/yellow ( little bit of electrical History )