Minding your own business is a good habit to uphold in life, and at work. For the latter situation, that could mean biting your tongue when your colleague insists on completing a project in a manner you feel is ineffective, or keeping quiet about the fact that his or her workspace is so cluttered you can barely tell there's a desk underneath.

But what happens when a co-worker's behavior negatively affects your experience on the job? At that point, staying silent becomes much more difficult.

It's a scenario you may encounter if you have a colleague who constantly seems to be out of the office, whether it's because he or she is reportedly ill, needs time to tend to a personal matter, or is somehow taking yet another vacation day. Of course, if that co-worker's frequent absences don't affect you, then there's nothing to say. But if the fact that your colleague is often out means you get stuck having to pick up his or her slack, it can certainly leave a bitter taste in your mouth. Here's what to do if you're constantly pitching in for an absentee co-worker -- and rapidly losing your patience.

Man in suit sitting at laptop, holding his head

IMAGE SOURCE: GETTY IMAGES.

Complain to your manager, not your colleague

The fact that you're left taking over your absentee colleague's workload is actually your manager's fault, not your teammate's fault. Your boss should have a backup plan in place for when employees take time off, so if you're the one who's constantly bearing the brunt of your co-worker's absences, that's something you shouldn't hesitate to address.

Explain to your manager that while you're happy to pitch in on occasion, you feel you've been doing it far too frequently for comfort lately. Also, make it clear that you're concerned that your own workload will start to suffer if you're regularly taking on assignments that should fall on your oft-absent colleague. With any luck, your boss will realize that he or she needs to either look into addressing your co-worker's excessive absences, or find a way to more equitably distribute the work that isn't getting done.

Furthermore, while you shouldn't directly complain to your co-worker that his or her frequent absences are messing up your work schedule, you can gently ask for a heads-up on planned time off so you can prepare to take over that person's assignments if needed. This isn't an unreasonable thing to do, especially if it's clear that you're the go-to backup.

Along these lines, it wouldn't hurt to gently inquire if things with your colleague are OK. For all you know, he or she is grappling with a chronic illness, an issue with a child or spouse, or a mental health problem, so while it may seem like that person is constantly out of the office for no good reason, there may be a solid explanation at play. Of course, your colleague doesn't owe you that explanation -- that's between your co-worker and his or her boss. But if you do find out that your co-worker has missed seven or eight days of work in the last month because he or she is dealing with fertility treatments, complications from a minor surgical procedure, or a nasty divorce, it might make you feel less bitter about having to step up.

Ultimately, you have every right to say something if a colleague is constantly out of the office and you're the one having to take over his or her workload. Just broach that topic with the right person (your boss), and with the right attitude, so that you don't end up looking bad in the process.