Sometimes I forget to list the variables names in the AMPscript block and they still work just fine. Can I go and not list any of them? Is there anything that can go wrong if I don't list any? 

I just wanna make sure I'm not missing something here. Thanks.

e.g.

```
%%[
Var @variable1, @variable2
Set @variable1 = "something"
Set @variable2 = "something else"
]%%

```

vs. 

```
%%[
Set @variable1 = "something"
Set @variable2 = "something else"
]%%

```