I think it really depends on the kind of job you have on whether you go into work when requested in. It also depends on your managers and how chill you are with them. Some managers are understanding that you've already made plans, and others will see that as a reason to dock you in their minds.
I'm in great standing with my managers, so I don't have to worry about any of that crap. If I'm even late by a few minutes for work, my managers would wonder what happened to me. I've got a clean record on everything and I've only called into work maybe twice in the past year and a half, so saying no to them means I've got a good reason not to go into work.
If you're already a lazy ass and you don't want to go into work, then the manager will believe the lazy bum stereotype you've set up for yourself even more so.