Investors pass on most decks in under three minutes. They rarely tell you why — "not a fit for our thesis" is the polite version of one of these:

1. They can't tell what you do

The most common killer. If slides 1–2 don't make a stranger say "oh, it's X for Y," nothing after matters. Jargon, clever taglines, and "we're building the future of" openings all fail the same test.

Fix: one plain sentence on slide one. "We help [who] do [what] so they get [outcome]." Boring beats clever.

2. No proof anything works

Claims without evidence are just wishes. "Huge demand" with no users, "viral potential" with no growth, revenue projections with no revenue — investors have seen all of it.

Fix: lead with whatever proof you actually have. Ten paying customers beats a thousand "interested." A waitlist with emails beats "the market is $50B."

3. The market slide is fantasy

"TAM $80B" with a top-down number from a research firm tells an investor nothing about whether you can build a real business. They know the trick.

Fix: bottom-up math. How many customers, at what price, reachable how? A believable $200M beats a laughable $80B.

4. The team slide doesn't close the deal

Investors bet on teams at the early stage. If your backgrounds don't obviously connect to this problem, they'll assume you'll figure that out too late.

Fix: every person gets one line tying them to this company. "Ex-Stripe, built payments infra for 4 years" — not just a logo cloud.

5. The ask is vague

"Raising a seed round to accelerate growth" is not an ask. Investors want: how much, what it buys (hires? milestones?), and what the terms look like.

Fix: one slide. Amount, use of funds tied to milestones, and what the next 18 months look like if it works.

6. The deck is too long

Thirty-plus slides signals you can't prioritize — which is exactly what running a startup requires. Nobody reads slide 28.

Fix: 10–15 slides for the send-ahead deck. Put the rest in an appendix you never open unless asked.