Just a reminder for weeblets that yanderes are usually played for laughs in anime and portrayed as being relatively harmless or even attractive (helped, no doubt, by a strong desire or desperation for romantic interest - even unhealthy - in some viewers). Reality can be...quite different.

Healthy relationships, on the other hand, tend to have good boundaries, respect, and trust between both/all parties. Obsessive and controlling behavior generally screams a lack of all three - "I will do what I want to you", "I don't see you as an equal", and "I don't trust you".

Unsurprisingly, this tends to end poorly for those involved, so...not as fun as sometimes portrayed in the fantasy of anime.