Being in Character - the Pros and the Woes.
One thing a lot of cosplayers and non-cosplaying attendees struggle with is figuring out where the line is when it comes to being in character.
It's always very exciting to be in costume at a con, but what happens when someone approaches you, and starts treating you like a character? Suddenly you feel as though you must become an improv master, as well as a total guru on whomever you are cosplaying. If you're comfortable with improv, this isn't a traumatic experience at all. Often, these people who seek to get to know the character and ask questions like "How you felt when Kyouya rejected you in episode 8?" will catch you by surprise.
Once, dressed as Dave Strider, I was in the middle of purchasing a hand-drawn yaoi Sherlock fic when a Calliope approached me. There are a variety of issues with this scenario. The first, is that I was horribly unprepared to be Dave Strider. It was a last-minute cosplay. The second, was that I was in the middle of purchasing somewhat explicit material when this Calliope approached me. And the Third, was that this Calliope attempted to engage in banter from the source material that I was unfamiliar with, as I hadn't even gotten to the part of homestuck in which Calliope was introduced. So it was an inescapable situation. I awkwardly played along until the Calliope wandered off and I was safe to go about my day.
This is definitely not the worst "in-character" interaction I've seen. I've seen harassment due to someone being a little too in character. Just because something is okay in anime, does not mean you can cross that line in the real world, no matter who you're cosplaying. Remember to always ask for consent, even if that's not in-character.
Another thing I'd like to say is No, you do not need to be in character if you are a cosplayer. Sure, it helps if you can muster up the ability to stay in character when you need to. It can also be super fun to stay in character throughout the day. By no means does that mean you have to be in character to be a good cosplayer. Lately, I try to cosplay Tsundere types because I have a terrible case of resting b!tch face, and therefore always seem in character. It helps to cosplay characters that somewhat align with your personality, but again, this is not a requirement. Just be aware that there may be someone who tries to interact with you as your character.
There is one occasion where you should ALWAYS be in character: around children (unless your character is super non-children friendly). If you are dressed as a popular kids character. Whether its a super hero, or a princess, strive to stay in character. You could make their con experience super special and they'll remember the day they met you for a long time. I like to check out convention demographics and if it's more of a family con, I will be sure to break out a disney princess cosplay one of the days. Cosplay in general feels good, but it feel especially good to make a child's day.