In all honesty, I have never seen a girl with a top showing where the bra straps should be without there being bra straps there. That was unclear, so I'll reformulate: everyone has always been wearing bras with straps from what I've seen. Apart from fancy dresses for special events, for example.
Many of them had a normal black, white, etc. bra with normal straps showing, and it looked fine. A few had a bra with transparent plastic straps, and it looked fine, although uncomfortable, because it looks like such a thin thing would "bite" into the skin a bit. Actually, more than fine, it looked good. For some reason I find straps coming out of a top (on men and women, be it bra or tank top or whatever) have sort of a cute look.
I think you might be a bit too focused on your bra straps.