Sunderland fans have a huge collective ego, if you read their forum you'd genuinely think you are reading a Man United or Liverpool forum. Its not just a big club mentality is a mentality of a an absolutely massive club.
God knows where it comes from, they have 1 major trophy in 86 years and that's known as one of the biggest FA Cup upsets of all time. They have no European pedigree and have been a yo yo club for half a century.
When you talk about a deluded fanbase they are right up there with the geordies.