For me it is when companies/services market themselves as donating to XYZ cause if I buy their product. If they want to donate, they should have already done that with the money they have. Asking me to give them profit so that they can donate is so obviously pretentious.
Sending my work email a calendar invite as the first communication. Just because you want to sell it doesn’t mean I want to buy it. Or even hear about it. If a calendar event is the first thing you send me, I will be the avatar of snark. My calendar is busy enough without you inserting yourself into it without my consent.
Double snark if you get upset that I didn’t accept it and reach out to find out why.