Strong, direct:
* Compelled: Suggests a strong force driving you to pay attention.
* Obsessed: Implies an unhealthy fixation or preoccupation.
* Haunted: Conveys a sense of being troubled or tormented by something.
More nuanced:
* Intrigued: Indicates a strong curiosity or interest.
* Captivated: Suggests a feeling of being completely absorbed.
* Engrossed: Implies being deeply involved or absorbed in something.
* Drawn to: Expresses a sense of being attracted or pulled toward something.
Informal:
* Can't help but notice: A simple and direct way to say it.
* Stuck on: Indicates a persistent focus on something.
The best word to use will depend on the specific situation and the desired tone.