What are the implications of different button sizes in terms of what the designer is trying to convey to the user and what the user is implying as to the function of the button?
For example, does a huge "Download" button convey anything different to the user versus a small button or is the button simply bigger to make it more prominent and get more clicks?
I suspect button size may sometimes correlate to the complexity of the corresponding action but I don't have any evidence of this other than my own observations. It does seem that large "Download" buttons tend to be direct download links as opposed to a link to the download page.