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.
To me it’s sending me e-mails I have not explicitly signed up for. I have had once or twice, when I had filled out a form to order something and without pressing submit, they had already registered my e-mail address and signed me up for all kinds of spam, starting with ‘weren’t you about to order something’.
Especially when they sign me up for a bunch of different emails lists I need to unsubscribe from each one individually and eventually just spam everything from them. Then they sell my email.
Use a different email alias for each site. Duckduckgo with their duck.com, or Apple’s Hide My Email makes that easy; let your password manager keep track of the alias. If they start to spam me, I know not to use that site again, and I can delete the alias so that the spam goes into a black hole.
I use my pets names. They frequently get special invitations for credit cards.