Guilt don't sell beakers

Sales reps are everywhere when you start a new lab. They come out of the woodwork and rapidly descend at the smell of start-up money, offering package deals and deep "new lab" discounts. In the end, you have to chose whether you go with a major company (like Fisher) or a smaller, local company. I ended up buying most of my equipment through a local company because they had decent prices and the guy I worked with took a lot of time to make sure that my lab got set up right. In contrast, some of the other companies had multiple people who presided over different product lines and it was a mess just getting a quote because any request had to filter through 3 or 4 people before I ever saw a response. I am happy with my choice and ended up filling my lab with equipment a lot faster than I thought I was going to be able to.
But I can't help and feel a little guilty when the other sales reps come by to chat, which they do regularly. I sat down with many of them in the beginning to talk about pricing and what I needed, so I know most of them on a first name basis at this point. Because my office is attached to the lab, they always find an excuse to survey where I am at. Most of them are pretty good at hiding their disappointment over the realization that I have already spent tens of thousands of dollars with a competitor, but not all of them. Like scorned lovers, they keep up a smile but are slightly deflated at the sight of a lab full of equipment with logos of other companies all over them. I'm sure I'll be jaded to this eventually, but one of the young Fisher reps is pregnant and part of me feels awful that I have bought almost nothing from her at all. I know that my account is not going to make or break anyone and it's not personal, but still.
The reps can be endlessly entertaining though, from an unintentional comedy stand-point, and I have mental nicknames for most of them. The bigger companies often send their reps in packs and one on such a team I mentally refer to as The Joker, mainly because she seems to apply lipstick with a spatula and must have failed coloring in the lines as a pre-schooler. Another rep I call The Shaker, because he visibly trembles with nervousness the entire time he is giving a spiel. I want to tell him that if I freak him out that much, it might be time to think about a career switch. On the other hand, I kinda want to bring him in for a product demo just to see if he explodes or sweats through his shirt or something.