Avoid Saying "Yes" to Coming to Work When Called In

Ever been called into work or are called into work a lot? This will tell you how to avoid being tricked into saying "yes".

Steps

Have a made-up reply in your head before replying to the phone message/or calling back.
Act casual. Act like your life's so hectic that you haven't got enough time to talk on the phone. If you talk too much, they'd think you had enough time in your life to take the shift.
Don't have any loud noise in the background. The manager or whoever is on the phone at your work might think you're at some party and might think you're drunk.
Don't get mad about them calling you. Just say "Sorry, but I had other plans made. If you had called me the day before and gave me notice then I might have said yes. But it's 7 in the morning and I need my sleep".
Don't fall for the old "you need the extra money" ploy. The managers or co-workers try that ploy too many times.

Never get angry on the phone. After all, it's not their fault that one of their employees can't work.
Take a few shifts now and then or the manager might fire you and hire someone more efficient!
Always be prepared for a phone call from work asking you to take someone else's shift for them.

Never delete the message and never call back and leave the manager in a sticky jam. It could cost you your job.
If you make up some lame excuse for not being able to take the shift, they might start gossiping about you being a liar.
If you refuse to take any shifts then it makes you look bad.