Hi,

Let's discuss some mistakes many people make(so that we can benefit and not make the same mistakes).

Two Common Mistakes I Find:

Browser Incompatibility- I can understand if the site is not 100% valid, but sometimes things like the float error is IE just mess things up badly.

No Contact Form- Most people do not have contact forms and they even forget to leave an email id.
What mistakes do you hate?

Cheers!