Yes, shoes without the proper socks is my main way to get blisters. I figured this thread was going to be footwear and socks too.
I didn’t know a bra can cause I blister , but I know that they can cause skin tags 
I thought this was about feet, also, which had been a misery for me. But I finally found an amazing blister bandaid called Compeed. Shipped from England so it takes awhile to get here unless you pay extra. I took off the bandaids yesterday and my feet looked better than they had in several months, with almost fully healed feet.
Well, if one wants to prevent foot blisters from forming, good, padded socks and proper shoes are key. I swear by Thorlo socks and SAS shoes.
Ok, back to blisters elsewhere.
Ok, to summarize the discussion thus far, @conmama should throw out the nasty, offending, blister-causing bra and wear thick wool socks instead.
Fortunately socks come in pairs.
Unfortunately, your dryer will eat one of the socks…
That’s why you buy all your socks in the same color and style, so you can mix & match those which survive the gremlins in the dryer. 
That sounds pretty funny. Who needs a bra when you can use socks?
Don’t even get me started on tube socks as a replacement for a men’s swimsuit… 
Back in the day, a coworker went on her honeymoon trip to Maui and came back scarred for life… 
Oh my God!!!
Threads certainly do take on a life of their own! Who’d have thought this serious topic could veer off so?!?! :-).
Well if the sock fits, wear it!
Well, to continue the sock story… Have you heard about or seen, (a vision forever scarred my optic nerve), the “sock man” in the Castro? He walks around the Castro wearing only a sock on…