There are many:
It has standard PowerPoint colors, you couldn’t be bothered to even try to make an effort
It looks so slick and professional, like an iPhone launch deck, that potential investors in your seed company start to wonder what you are hiding (and how smart your spending is)
It is clear that you made a tremendous effort to make things look slick but all those gradients, shadows, clip art, and icons somehow still do not look right
Those curly accents, mint green soft fonts, and cute images look pretty but it does not seem right for a semiconductor company that needs to pitch to global device manufacturers
The spectacular animations that keep on moving and/or these clashing colors unsettle the audience’s central nerve system