I thought I had a great understanding of regular expressions but today I tried to use them in vim... Why the fuck they have to be so different there??

Prepend \v
Should solve your problems

Regex is like ice cream. Everyone has a preferred favor. Or they're lactose intolerant and index into strings all the time.

I have been trying to follow my own advice and avoid learning regexp so I don't have to use it. I have been moderately unsuccessful in my attempts. At least I have managed to limit myself into using some online helper instead of trying to understand what is actually happening.

@metamourge noted, thanks.