When do fans over step their boundaries?

micro managing their career etc.

Quote from ohpuhlease

And when they copy tattoos of their faves…. Idk if this is weird but I find it weird

I do find it a little iffy. Tattoos are personal and the idol got the tattoo because it was personal to them. So then why is the fan getting a replica tattoo that has no personal meaning for them? People can do what they please with their bodies but i just find it confusing.

Invading an artist's (and their family and friends) privacy and personal space (be it online or in real life), micromanaging and what I've noticed lately, projecting your own beliefs and ideals onto them.

When fans thought they own their idols just because they bought their albums, merchs, stream their songs & MVs etc. and when their expectations were not met, they throw a fit!

When fans call sneaky pics taken during idols' personal time "updates"

Pretty much everything you've mentioned.

Preaching to them over their lifestyle choices especially.

For example fans trying to tell an idol the dangers of smoking and a thousand reasons why they should quit like the person doesn't already know. Such things are at times not even that welcome from you own family.

Or those fans that try to preach their own religious beliefs to them in weird ways that are clearly over the line. I've seen some fans legitimately writing prayers for BTS members to stop eating pork and drinking so much because it's Haram and they don't want them to go to hell. Or the fans who try to give them bibles and convert them to Christianity and bring them back to god (in the case of Namjoon especially).

Also the fans who try to control their faves friendships and relationships are way out of line.

Like you're just a fan, all these things literally have nothing to do with you.

Some interesting points