There are many calm places not overcrowded and its no problem to find an empty plage if toi have patience, but in Visby (the biggest town) there are pubs, restaurants and clubs everywhere in the summer.
Video of an exchange student in Sweden where he "swear alot and get lost." Hang on... that is normal if toi are in Lund studying. BE WARNED: If toi don't like swearing, probably best not to watch