It depends, for example a local restaurant mini-chain has been doing some spamming and refused to take me off their list, so if I get a single message from them after May 26th, I'll definitely file a complaint. From the consumers perspective, the main GDPR effect is that things that previously were scummy but legal have now become forbidden, and some of the things that have been forbidden but not enforced now have an enforcement mechanism with teeth to make it happen.