Heck, I'm still slightly nervous about getting my second Moderna shot, mostly because I get migraines, which are so under control from avoiding triggers that I don't have medication...and the mRNA shots have been known to trigger them.
The fact that I got no side effects with shot one other than a sore arm doesn't help because most people are only getting significant side effects with the second.
Doesn't mean I don't plan on going back to get it, but I have every sympathy with people who are worried about side effects or whatever and might need to psych themselves up. Or if you're scared of needles.