School teacher hands down for me. I actually took time off my regular job to volunteer-teach math at a local elementary school. That doesn't mean it's the right answer for you, because Store Manager is a good job, too. But see if my reasons make sense to you.
Why I would want to be a teacher:
I was a natural tutor - friends came for me to help when I was in school.
I'm reasonably good at being entertaining, keeping people's attention.
Teaching impacts the future. A student could grow up to do something with huge impact. 499 of your students might go on to be ordinary, but one might invent the solution to clean energy.
In a good school, you are revered by parents and students alike.
Drawbacks of being a teacher:
Pay is not that great, possibly not enough to live on in some areas. There is little chance for advancement in the public sector, unless one moves into administration.
Need to have extreme patience. Not all students listen.
If you are put in a difficult school, you could be given impossible goals for student achievement, then blamed when those are not met, both by the administration, and parents.
Why I wouldn't want to be a store manager:
I would have constant public contact, and would have to dress up.
Retail employees are often unreliable. The manager has to deal with people not showing up, quitting on the spot, and covering the absence. Some of it is like babysitting.
Managers have to write reviews of employees. They could hate me if it's not what they expected.
Managers have to fire people at times. I might have to fire a single mom for not showing up, when I know it would mean she couldn't make rent, and would become homeless.
Managers have to enforce company policy, which may not line up with their own personal beliefs. I might also be barred from becoming too friendly with the people at work.