#Fediverse etiquette varies almost per individual IME, so I err towards unobtrusive. Don't want to bug folks who don't want to be bugged, but do want to be able to read/support interesting folks. Hence, I sometimes follow without an initial interaction.
If I follow your profile w/o a proper intro, it's likely because
* You interacted first, I read your profile, and think you're neat
* I somehow randomly stumbled across your profile, read it, and think you're neat
* You're a creator or content outlet that I want to support
Point being, it's out of genuine interest in you as a person/entity.