caching, when does it become a hindrance?

hey everyone, i've been thinking a lot about caching lately. we all know how crucial it is for performance, but i've seen situations where adding too much or the wrong kind of caching actually slowed things down or made debugging a nightmare. what are your experiences? when have you found that a caching layer started causing more problems than it solved? are there specific patterns or metrics that tell you it's time to re-evaluate or remove it? looking forward to hearing your war stories and strategies