Poll: What do you find buying online really hard or annoying?

I'm building a shopping site because I find online shopping for some products really frustrating. The idea is to have one site where you can search for all options for a given product category and quickly filter down to the one you want to buy.

I have some product categories in mind that I would like to work on, but I want to know what you would find useful.

Please vote for one or more of the following and comment below to say what you find most frustrating about buying that online. What would you like to be fixed?

Thanks!