conditioner were customary to me.
I think you could try 'are' since the detailed description before makes it to understand you're remembering the exact moment. Just a suggestion, not necessary.
Feeding a computer names...
Maybe: Feeding names into a computer... the sentence structure makes it less confusing (again, not strictly necessary.)
isn't a job people would want to do
isn't a job people
a lot would
like to do (you seem to be generalizing; who knows? Maybe there's someone that enjoys it.)
especially in their free time
especially
during their free time
all in my free time at school
all in my free time at school
accomplishment; in addition to that, I made friends with a couple of students and teachers.
accomplishment
. In addition to that, I made friends with a couple of students and teachers.
The essay is pretty good overall, though I think that's a pretty poor conclusion. If you didn't talk about it in your whole essay, perhaps it shouldn't be the definite end? Maybe you could say something like 'All in all, I found that I could get many things out of working a job many people would consider dull' or something along those lines.
Good luck!