Careerbuilder, the job-hunting website that I - and perhaps you - occasionally utllize, often contributes articles to MSN.com on work-related matters. At the link below, you will find a piece that warns you not to be too much of a nice guy (or "altruist") at work - especially if you're an American. According to one researcher, "Nice gets you in trouble. Nice gets you exploited."

Here are common modes of being too nice - with my own annotations:

1) You Let Others' Mistakes Inconvenience You - Actually, even not-so-nice people (like me) use this tactic to their advantage. The mistakes of others can give you the opportunity to outshine them by retrieving their fumbles and completing the play. It can also give you the satisfaction of feeling smarter than the idiots around you.

2) You Let Others Take Credit For Your Ideas - I agree here. This is never a good thing, but it's generally inevitable in a hierarchical situation. Make the best of it however. If you let someone take credit for what you did - particularly if the culprit is a colleague or a manager just a notch above you - play the emotional blackmail card to the hilt and make sure they know they owe you.

3) You Apologize Unnecessarily - It's always better when the other guy makes the mistakes. If you make them, never affix blame to yourself if you can. Be clever enough to identify extenuating circumstances that nobody else would have thought of, and your gaffe will appear like the inevitable setback of a pioneer - not the pratfall of a clueless doofus. Only apologize when you obviously don't need to, imbuing your apology with a barely detectable tinge of sarcasm that implies that the one you're apologizing to is more to blame. This will help you amass emotional blackmail capital for the future.

4) You Work Without Breaks - If you're inclined to do this, make sure you're paid on an hourly basis. Long hours with no vacations can be a fool's gambit for a salaried employee, but it can be gravy train for a contractor. Establish a reputation as (relatively) indispensable first - perhaps by doing a lot of Number 1 above or Number 5 below - and you'll be able to milk the sow of the corporate consulting budget for all it's worth.

5) You Do Others' Work For Them - Do this only if you know you can do at least as good a job as the person you're doing it for. Like correcting others' mistakes, taking on others' assignments is conquest by territorial annexation. The more that your employers depend you to get done, the more "indispensable" you will appear.

"Stop Being So Nice to Your Co-workers" from MSN.com