They really are not your friends -- they are very good salespeople (as mentioned in the other comment).
One of the most famous SV VCs who is pretty much a household name and has the image of -> kind guy shredded our founder to pieces. It was baffling to watch but just shows how ruthless they can be in the face of adversity.
It's very important to understand that once they show interest it means they need you as much as you need them. They're just very good at marketing and putting themselves in a position of "King Makers". Be confident when you talk to them ;)
Assume things will be structured to favour the VC.