Obviously leaving aside the rule that you should wear what you feel good in etc.
I think a bit of bra back, strap or even cup showing is fine, especially if the bra is pretty (and clean!). But I've seen a few things recently that I think are downright odd.
- Strapless dresses worn with non-strapless bras
- Tops with skinny straps worn with bras with scaffolding-width straps
- Backless tops/dresses worn with ordinary, non-backless bras
- A dress with a string bikini-style top worn with a strapless, nude, molded-cup bra - and I know this because acres of the cups were on display
It's a huge gripe of mine because I love backless dresses/tops and so many of them are just impossible to wear unless you go braless. And I hate the fact that large-cup bras all have such thick straps. Should I just get over myself and display my bra with pride? But I think it looks AWFUL.