I also hate the way WH Smith have largely stopped giving out receipts - presumably to help the environment and save paper (and, if you ask for one, they sometimes look at you like you've asked them to name the 43rd largest city in El Salvador) - BUT they still give you lots of (not very competitive) offer coupons, without ever asking if you want them. Even more irritating if you wanted/needed a receipt and assume the paper they pressed into your hand after you paid included it. The self-service tills (that hardly anybody ever seems to use, even if there's a big queue) are always covered in ignored spat-out coupons and offer slips. Even they ask if you want a bottle of water for 95p or whatever before you can pay for the goods you've actually selected to buy; it's not even like the water bottles are next to the till as an impulse buy, so you'd have to agree to it, be charged and then leave the till to go and find one.
I shall miss some elements of Debenhams, but most certainly not the constant badgering to get a store card. The big (only) selling point was always the 10% off your first purchase, but they'd try to sign you up (obviously ordered to) when you were spending £5 on some pants or something. Yes, I'd love to be delayed for 10 minutes and sign myself up to a load of marketing communications and spam to waste my one single benefit of it and save 50p. Presumably, the big bosses thought (if they did at all) that people would hear of the 10% off and say "Ooooh, pause the transaction - I'll just leave these pants here and go and quickly gather another £3,000 of random items so as to maximise my discount!" Of course, in the real world, people just have the perfect reason to decline at that time: if they do sign up, they'll wait until another time when they're buying a lot more.
The additional insurance cover at Argos always irritates me. Leaving aside the fact that, if you're spending £1K on something, you'd normally want to examine the proposed policy, see what it covers, decide if it's appropriate for your requirements etc; you can buy a cheapo toaster for £6.99 and then be asked if you'd like to pay another £2 to 'protect' your purchase. Why ever would you?! Who would go to all the hassle of returning it and claiming in the first place? They once asked me if I wanted to pay £7 to insure a cupboard I bought for £40 in case it failed/broke down/went wrong within the first 3 years. I was genuinely bewildered. I think I said out loud several times; "But it's a cupboard?!?!" and must have sounded quite mad 
Sadly, I agree that complaining won't stop the bosses from doing it in the least. They see the tangible results of increased profits from the very small number who do capitulate, but the massive lack of goodwill from huge amounts of people (almost everybody) getting mightily irritated by it - and often deliberately avoiding their shops because of it - will all slip completely under their radar. If they do think about the latter group, their response will be to be even more draconian with their staff on their till to strongarm more added sales, as 'that's clearly what's needed'.
You might be a customer, who keeps their shop going in the first place - even one of a thousand customers complaining; but firstly, they will consider the majority of the customers who don't have the time/energy/will/knowledge/just cba to complain (possibly because they know it will do no good anyway), but are mostly still just as irritated as happy customers, ergo 'the vast majority of our customers WELCOME the chance to be offered additional purchasing opportunities'; and secondly, they have experience and maybe qualifications in marketing and you likely don't, so nothing they think will work can possibly be wrong, however many ignorant plebs (the ones actually spending the money with them) mistakenly tell them.