Over the years various shops grab your email address and add you to their marketing list.. I've been having a week of unsubscribing from them all to an effort to avoid inbox noise.
Best one so far are:
Asda - 2 hours later get an email telling me they have changed their email address - thanks!
Jessops - send you an email confirming I've been un-subscribed.
John Lewis - send you an email which you have to click on the link to confirm you want to leave them!