One trick restaurants do is called anchoring.
Here's how it works:
-Surf and Turf........................$45.00
-Salmon..................................$28.00
-Fish and Chips......................$16.00
You see how the most expensive item is on the top of the items on the menu?
This is no accident. The menu's author placed the most expensive item that is far more expensive then the other two items.
Once you see this, it sets a ceiling in your mind for the highest price. After that anything you buy even if it is an over priced plate of fish and chips, you'll still feel like you were being conservative because you didn't select the highest priced item on the menu.
To avoid this trick look for the lowest price item on the menu first then gauge how high it is relative to other restaurants offering a similar dish.
