1. Application and enforcement: GDPR is 100% arbitrarily enforced, it is a "trust us, we could do no harm, trust us" law, that is extremely well suited to adding other such "trust us" laws.
2. Absolutely ridiculous overreach: on a technical level, GDPR is braindead. It applies ridiculous, stupid and unnecessary restrictions for no purpose.
3. You just added an obligatory "lol accept this or GTFO" thing to all sites.