No, but I won’t do an investment < 7.5-10% unless it’s an “exception”. Exceptions could include (x) already know founder, (y) was a pre-existing investment, which is sort of like the last point, (z) am a super-fan of the product/team and/or (aa) reasonably likely chance to buy more later.
The real reason is there is only so much time, and it’s too hard to make enough money with very small ownership stakes. Unfortunately.