I built this garden shed to hold potting supplies and lawn tools for my bonsai garden. It was a fun exercise playing with the nail gun and I didn't even stab myself. The shed definitely is not plumb or square, but it hasn't fallen over yet so I'm pleased.
As someone who's naturally anal retentive I would say repeated DIY projects have convinced me minor deviations are usually unimportant given everyone, even the honest asshole, seems unable to spot them w/o my assistance. Even then it's 50/50 whether they think they're obvious.
Long story long.. Your shed looks great, it's simple yet has some interesting details, & I'm sure it'll stand for many years to come!
Everyone often overstates their little mistakes, but you're right, they're rarely noticed. Just think of every blemish being a lesson you'll remember for next time.