In Finland, tips are not expected, not even in restaurants - service is always included. If you feel you have received excellent service or someone really has gone out of their way to help you in a taxi or in a restaurant, feel free to tip - the recipient is normally pleased.  But if your tip is declined (which has happened, even in very tip-worthy situations), don't push it... Tips are often seen as insulting, as if implying the person only helped because of hope of a tip when e.g. he really just wanted to be nice to a foreigner.