What is the point of revving your engine at an oncoming modified car?

[Catnip]

I don't get any revs.
If a car in my league is next to me at a light though, it's almost always assumed that it's a race when it goes green. Eye contact isn't needed.

lolol

The funny part is, no one even launches... just rolling out and both hitting it at the same time. Like a simultaneous pissing contest.