AutoPlay sliders, taking over user control, slapping them with messages, even text alignment plays a role in customer experience. Since your website is often their first experience with you, why make it difficult, slow and hard to navigate?
If it's not done with a purpose for a potential customer or client, there's no reason for it to be taking up room on you site.
Don't hide your form behind a button on a pop-up, if you want them to fill out your contact form, put it on your contact page.
You should never sacrifice your content for an image. If the image is that important, put it in a column or it's own section.
If any of this is on your site, you're throwing money away.
If you didn't click the first 2 this one is sure to seal the deal right?
Please?
WE NEED CLICKS!
Here's a secret, Your customers won't either. It's just annoying them.
They may remember your site, but it won't be for good things.