First of all, the OP, and some posters are generalizing about Europe. Credit card theft happens everwhere. There isn't a "credit card theft hotbed" somewhere in Europe or elsewhere for tourist...

My suggestion applies to both domestic (USA) and elsewhere (Canada/Europe):

Feel safe using your credit card at chain hotels, supermarkets, self-serve gas stations, and department stores. Also feel safe using your credit card where the "swipe" is done in front of you, and the card never leaves your sight.

Feel unsafe using your credit card at smaller businesses where the equipment might be tampered with, or where they take your credit card away for swiping (most restaurants in USA).

Carry enough cash to cover meal/transportation/getting you back to your hotel. and if it doesn't feel right, don't use your credit card... If you carry enough cash, you will have to worry about getting pickpocketed and mugged as well. You mind as well not leave your bed. :-)

Ultimately, confirm what you are signing, and keep a copy of the receipt. Check your credit card statement regularly. Don't worry too much about events such as the Target account hack. Your USA based credit card company mostly have you protected.