Why You Should NOT Go to a Writing Conference
Money
If cash is an issue, then don't go. And don't get all mopey and poor me and throw an uber pity party. Suck it up and move on. Maybe you'll have the moolah next year. If it comes down to a choice between attending a conference or paying your rent, the rent should win every time. Conferences are a luxury, not a mandatory requirement to be a successful author.
Validation
Going to a conference does not make you a "For Real" writer. Writing makes you a writer.
Unreasonable Expectations
Just because you attend a con doesn't mean you're going to land a contract. The opposite might happen and you'll be told your writing sucks. Reasonable expectations would be that you intend to make new friends and learn more of the craft. Anything else is unreasonable. Do not go to a conference expecting to be the belle of the ball.
Peer Pressure
I know. It's hard to skip out on something just cuz all the cool kids are doing it. But if you're only going because your friends are, then don't bother. Not that hanging with your peeps isn't an essential activity, but if that's your only reason, then it's not worth it.
Margin
If you've got deadlines galore, or family events, or school's starting or whatever, put some margin into your life and just say no to the conference. Adding a conference onto your heap o' busy adds stress. If the needle on your crazy-o-meter is currently in the blow up zone, then don't go.
Don't get me wrong . . . conferences are great. I'm just saying don't freak out if you can't or aren't able to attend one.