yuurionviktor:

maybe i should have explained it in post itself haha

Well there are a lot of forms of pet-names in russian and all of them usually have different sense-feelings?

Vitya  is a colloquial form of a name Victor that can be used by friends or colleagues of the same age/older or generally older people he knows. Or generally in the informal situations.

Viten’ka is  diminutive form that can be used by family or really close people/lover.

Vityanya is also colloquial form but it can be used(maybe! if person is okay with that) only by close friends and it’s kinda disrespectful, very informal and  unsophisticated.

Vit’yok same as Vityanya but twice as informal and a little rude. It also has a very strong slav/gopnik vibe as was pointed out in replies. So that makes sense for our Victor to be offended.

There are great posts about that:  1 2 They are way better than my explanation and i really recommend reading them if you’re interested in this subject!