Usually the main problem is on your internet connection. If you have slow internet connection, the website won't load or even only load a half of it, so your website will look like a little bit messy. Take an example if you load one website full of image and graphic, for slow internet connection it cannot be displyed correctly, but when you have fast internet connection, then the website will be displayed correctly.

So in conclusion, try to use fast internet connection and you will have no problem with opera.

source: based on my own experience about the same problem.