Why do people dislike Wells Fargo?

It is based on some really shitty stuff the company did several years ago. Because of the way their "sales culture" was structured, it became common for employees to open up accounts for customers without their knowledge (e.g. someone has a checking account, and the employee opens a credit card for them as well, without consent). This became endemic to the point where millions of fake accounts were opened without permission.

Thousands of employees were fired, and the company faced a series of record fines, and were excoriated in the media. This all happened in the early to mid 2010's.

But, the reputational damage was done - and to this day when the name Wells Fargo is brought up, it's often the first thing people think of as they are spitting at the ground in contempt.

Wells Fargo has updated their policies and practices, so the same incentives that led to this out-of-control behavior can't really happen again. In many ways it is a different company. But the name Wells Fargo is tarred forever with this massive black mark on their reputation, and there will always be people who hate the company based on what they did (and stopped doing) a decade ago.

All that being said, today they're pretty much like any other big bank - similar to Chase or BofA or Citi or PNC or Citizens, for example, in terms of the number of complaints and the types of problems they face. It's just Wells Fargo has this added extra baggage from their past bad behavior on top of that.