Terror is a strong word, but it sounds cool combined with tram :-)
But there is a need to be careful if you are not used to trams. People are run over every year because they don't pay heed to them in traffic.
If you just check for cars and then walk you might walk straight infront of a tram and heavy as they are they do not stop instantly.
They are not dangerus, just remember that they are out there and there will be no problem.
Although they do have an excellent Tram-System in Göteborg, don't even think of playing the Anarchist by hopping on a Tram while enjoying your tasty Triumf Glass Båtis, lest you be prepared to suffer the voice of God condemning you to 50 laps in a lake of fire.(without your ice-cream!)