Based on the context and the answer, generate a question. 

Context: That was my first time to go to any anime - related convention , so imagine my surprise when I got there and people were dressed up in full cosplay attire , while I was in : T - shirt , shorts and slippers . LOLz . And it was more of the " I just decided to put on clothes today , because ca n't just leave this house naked " kind of shirt and shorts ... whereas everyone else had nice clothes on .

Answer:

An anime convention with many people in cos - play outfits has a playful atmosphere .



What is the atmosphere at an anime convention where many dress in cos - play ?