An investor double-clicks an attachment, you make a first impression already which is totally disconnected from the idea you are trying to pitch:
- The slides have a reasonably professional feel: not the standard Microsoft Office template, not a 1990s bevel and gradient template, no times roman font, slide formats are more or less consistent throughout the presentation, images are not cheesy and/or stretched
- The slides have a grown up language, which shows that the author understands the audience: no padding with buzzwords, no 101 introductions to a subject that any VC is supposed to master, no presentation cliches ("in this ever faster changing world where we all have become digital nomads")
- Early in the deck it is at least clear what you are doing
- The email addresses are not gmail, and the company domain has some sort of place holder in a consistent look & feel with the presentation. LinkedIn pages of founders are consistent and up to date.
- You are sending a PDF, not a PowerPoint document, and it fits in a 10MB file
These are examples of the digital equivalent of the first impression you get with a handshake. Your deck is compared to all other decks this VC has seen in her career in more or less a second. And she has developed the intuition, what sort of decks usually are associated with good deals, and which ones to avoid.