This is a story about the lives of others...
The more a person spies on another person, the more they see themself reflected back. The more they sympathise and see the ordinary humanity in the person that they are spying on. The more empathy they feel, the more they start to doubt the ethics of spying.
We can use software to do a lot of the 'heavy lifting' of spying, but we still need intelligence officers to actually then do in-depth analysis after red flags are raised by the systems that monitor our electronic communication.
These analysts may then be sanctioned to perform further, more in-depth snooping, if there looks to be a strong case to justify the further intrusion into the life of that citizen. They have to argue the case to their superiors. They also have to argue the case because it's their job to make cases. If they didn't think anybody was worth spying on, there wouldn't be any jobs in the intelligence field.
When a case is accepted, then even more information is gathered, sometimes at great expense. Then, somebody has to pick up the bill. It's time to start building a case now against that person, to make them pick up the bill.
The usual ways that the intelligence agencies will make their citizens pay would be prosecution for terrorism, fraud, drug trafficking, prostitution, human trafficking, weapons. Unfortunately, this can also extend to anti-establishment activity, which would not be criminal. The only payback would be a smear campaign, which is a lot easier if you have lots of juicy details about that person's private life that you have snooped without their knowledge.
There's never any backing down. Nobody will ever say "On reflection, I was wrong and we should not have pryed into the private life of this citizen" because nobody wants to look stupid. Everybody wants to justify the case that was made and actions that were taken.
All I'm going to say is this: I'm only human, and I've never engaged in organised crime or terrorism.
That is all.