Where does chivalry end and sexism begin?

Everyone says chivalry is dead. In this day, I wouldn't necessarily say that it is dead, but it does seem to be on its way out. In my experience, it's rare to find someone who still opens the car door, gives up their seat, or makes the extra effort to hold the door open a little longer. In fact, some people today actually despise that kind of treatment, saying they are perfectly capable of opening their own door(s) or finding their own seat.

I'm not sure if women can be "chivalrous," but I suppose I would qualify. I always say "excuse me" when I bump into someone or squeeze past them. I hold the door for other people, even when my arms are full. If somebody nearby drops something, I pick it up for them. I let the person with one item go ahead of me in the grocery store line. I don't do it to get a pat on the back; that's just how I was raised.

At the store where I work, people often purchase very large, sometimes awkward, and usually heavy bags or plants. One of the services we offer is a customer carry-out; if someone does make a large purchase, we carry it out for them. I am one of only three women who currently work at this particular store, and, just like the guys, we are expected to help customers carry out their purchases. No problem; I grew up on a ranch, my parents own a feed store, I'm used to and actually enjoy a degree of physical labor in my day-to-day job. Generally, customers refuse at first, but when we insist, they usually hand over the large bag and settle for opening the door. Every once in a while, however, there will be one customer who refuses to let a girl help them.

When I tried to carry out an older gentleman's 25 lb. purchase, he literally took the bag out of my arms and said, "I can't let you do that, you're just a little girl!" I stand about 5'7" and weigh around 140 lbs, so it might be safe to say I'm not exactly "big," but I was a little stung by his comment. I would guess he was in his late 60s, early 70s, so I knew it was just a generational issue, and decided to let it go.

A couple weeks later, however, a man came in who couldn't have been more than 10-15 years older than me. I went out to load two 50 lb bags of fertilizer while he backed his truck up to the pallet. In my already-dirty jeans and company sweatshirt, I wasn't worried about the wet and messy bags from outside. The customer, however, was in khakis and a red and white checkered button-up shirt. Naturally, I assumed he wouldn't mind me loading the bags for him. After I threw the first bag over the edge of the pickup bed, he came rushing out of his truck and again took the second bag out of my arms. I assured him it was all right; I was already dirty and happy to load the second bag.

"I'll never be able to show my face in polite society again if I let you do this!" he said. I walked back inside with my dirty fists clenched. I'm sure these people are just trying to be polite and do as they were raised, but I find it extremely frustrating, and there is enough of a feminist in me to find it slightly offensive as well. I'm pretty sure it isn't just a size issue; of my two female coworkers, one is somewhat larger than I am in height and weight, and the other is smaller than I am in both as well, and I have seen both of them go through similar experiences. I have never, however, seen a customer take a purchase away from any of my male coworkers or refuse to let them load it.

This realization raised a question in me: where does chivalry end and sexism begin? Apparently, I'm not the first to try and tackle this question.

When does refusing to let a girl carry something heavy--even though she is getting paid to do so, and incidentally will get in trouble with the boss if she is caught failing to do so--cross the line and turn the man (I don't mean to be sexist myself, but so far, it has only been men) from a "chivalrous gentleman" into a "sexist pig"?

If anyone has any thoughts or stories, I would love to hear them!