If we're going to be honest here, many comics/movie/television/video game fans have negative attitudes, or at least fall into complaining and/or snark so easily that they can be Debbie Downers. Even creators, when speaking with one another, often grouse about how a convention is going for them, how it could be better, how it's not about comics anymore, or even how they should have just stayed at home. Well, they might have that last one right.
Don't be that person.
Sure, frustrations abound at comic conventions. There are lines for everything from signings to bathrooms. There's never enough space in the aisles. There are too many fans of that thing you hate, and not enough of that thing you love. You couldn't get into that super-important panel because no one left the room from the panel before. Your booth location doesn't get any foot traffic. You spent an hour in line for food, and they sold out of the last hot dog right in front of you.
Relax. Take a deep breath. Find the positive.
The short time you're at a comic convention should be tremendous fun, even with with minor hassles involved. Relish every moment of it. If you find yourself drifting into wet blanket territory, change things up. If lines are a problem, find an activity that doesn't have one (despite appearances, there are plenty). Having trouble navigating the aisles? Use the lobby for a clearer walking path. Shut out of a panel? Pull out your grid and find another. Heck, there's one time slot in the upcoming San Diego Comic Con in which there are three panels I want to attend.
Keep that positive attitude, and use it when talking with others about comics, too. Comic conventions are one of the few opportunities that us geeks have to sing the praises of our favorite properties to an audience that might actually be interested. Yet so many attendees become hyper-focused on whining about stories they didn't enjoy. In conversations, focus not on the stories you find disappointing, but on those that you love. Create new fans for your favorite characters, creators, or stories through your positive attitude.
That's what a comic convention should be about. Spread the love of a story, a character, a creator whose work you enjoy. Bring new fans into the fold. Enjoy the time with like-minded people, even impenetrable throngs of them. Most of all, have fun!