There are tiny little rules that every designer should stick to and nobody will get hurt. Like the rule that says "If it's a button, make it look like a button".
In this example from ticket giving touch screen terminal at #SwissPost one can see three options.
This #UX always flips me over, because for my brain the button on the top does not look like a button. It does not have the border as the other two buttons. It's visually different size than the other two. So my brain does not register it as "clickable something".
As a bonus thing we can notice that the buttons have only printed on them the logos of said companies. So if you're not familiar with the logos, you will have no clue what you're looking at. Take the Swiss Post logo as an example. It looks like "+P". How am I supposed to know what that means?