Buy it
As I was getting dressed this morning, I realized that my standby Calvin Klein nude bra that I wear under tank tops (it has nice thin straps) was totally shot--the cups were gaping and all elasticity appeared to be gone. So on my lunch hour, I headed over to Lord & Taylor to purchase a new tank-top-appropriate nude bra. (Now, before you make fun of me for shopping at the grandma-ish Lord & Taylor, let me just say that they're making a good effort to be more hip. Also, it's the closest department store to my office, and I had coupons.) Here is a brief re-enactment of what went down.

Saleswoman: Can I help you?
Me: Yeah, I'm looking for a nude bra with smooth cups, thin straps, and good support, in a D-cup*.
Saleswoman: Okay, I'll show you a few.
[Saleswoman proceeds to lead me around the lingerie department. I mention that I like Chantelle bras, so we go over to those.]
Saleswoman: What size do you need?
Me: 36D
[Saleswoman looks me up and down, frowns.]
Saleswoman: You're not a 36D.
Me: Yes, I am.
Saleswoman: I don't think so.
Me: I've worn a 36D for, like, eight or nine years.
Saleswoman: You've been wearing the wrong size. Seventy-five percent of women wear the wrong size bra.
Me: Okay, then what size am I?
[Saleswoman looks me up and down again.]
Saleswoman: You're a 34D. You have a small upper body.
Me: Okay...but can I try the 36D just for comparison?
[Saleswoman rolls eyes.]
Saleswoman: Fine.

So I went into the fitting room with, like, eight bras, all of them in both 36D and 34D. Lo and behold, all the 34Ds fit me perfectly. I literally couldn't believe my eyes. My breasts were uplifted like never before, the cups fit perfectly without puckering, and I didn't jiggle when I walked around the room. I have never felt such joy in buying lingerie (and I am quite a big lingerie fan to begin with). I wanted to buy all of the bras, but settled on this one. Seriously, it was like that episode of Sex and the City when Miranda's mother dies, and she goes to buy a black bra and the saleswoman tells her she's wearing the wrong size. Um, except for the funeral part. Anyway, I thanked my saleswoman profusely. She just smiled and nodded knowingly.

Moral of the story? Those old-lady saleswomen at Lord & Taylor have probably been working there since the sixties, and they know what they're talking about. Also, buy a bra that fits: It will change your whole outlook on life.

*I am not in any way bragging about my boobs. If you want an earful, I can tell you what a pain in the ass--or back, rather--they are.