Many employees confuse assertiveness with aggressiveness. Here's a lame attempt to explain the difference.
I've written a lot lately about the degree of assertiveness one needs to succeed in a career. I get a lot of negative feedback from non-aggressive types defending their work style. It makes me think that perhaps I'm not being clear in what I mean by "assertive." Assertive does not mean aggressive (sometimes it does, but not always). Assertive does not mean cruel or self-serving either.
Let's use a simple, yet stupid metaphor to illustrate the difference. (Hey, it's early, this is the best I can do. Take it up with the doctor who ordered me off caffeine.) Let's say you're trying to escort a little old lady safely across a crowded street. (For the purposes of my simple, yet stupid metaphor, this crossing will occur in the middle of a street, not at the light where you would have the benefit of a crosswalk. I like to live dangerously.)
If you are the hyper-aggressive type, you'll drag the poor woman by the arm, weaving in and out of traffic with only centimeters between you and moving car bumpers at any given time. You arrive at the other side of the street alive, but with a badly shaken old lady (possibly with a dislocated shoulder) and about a hundred commuters who hate your guts. Not exactly a successful endeavor.
So let's go back to the curb. Let's say you're a very timid, very unassertive person, afraid to take any chances. You're so afraid of hurting the kind old lady that you barely make any moves at all. You wait until traffic has died down (about four hours) and then you gingerly lead her across the street. By this time, she's drenched in rain, practically frozen and completely disillusioned by your attempts to "help." You've caused her to be hours late to her doctor's appointment, which will then put her way behind on her hair appointment. She will also miss her granddaughter's piano recital because of you.
Now let's get this poor woman across the street with a person who knows the meaning of assertive. You securely tuck her hand around one arm while you raise your other hand to stop some of the slower moving cars. At this point, you guide her safely to the other side. She's gotten to her destination a little faster than she would have if left unassisted because she was in your capable care.
In both aggressive and meek mode, you achieved the goal at hand, but you did it so poorly that that poor old lady will never ask for your assistance again.
That little old lady is a metaphor for every project you're involved in. You might (might!) achieve your desired result but the way you did it will affect others' perceptions of you may not be asked to lead any more projects.