|Show you care - give a compliment in his/her language! ©|
On the other hand, knowing how to give compliments in the language you're learning will help you in many other ways. You'll be more respected, you'll make more native friends and you'll have more to talk about. It's the total opposite of swearing (well, even some can appreciate that). Being nice is not a crime, believe it or not.
However, don't start over-complimenting people. Only give genuine, sincere compliments.
My video about Dutch compliments and flirting:
My video about German compliments and flirting:
My video about French compliments and flirting: