My sister maintains that if you are wearing a tank/vest summer top, you should not expose the normal white/black/coloured straps of your bra, especially if they display adjustment buckles etc.
She asserts that you should either: go strapless (horrible, unsafe & wobbly), use a rear strap clasp to pull in the straps (difficult to install & uncomfortable) or use clear bra straps.
I find the latter really sticky & clammy and they don't provide strap-free or buckle-free shoulders.
How do you wear your summer tops?