It's actually pretty simple. "Where I can't interpret the tax code myself" means "where my attempt to interpret the tax code leaves me with two or more possible interpretations."

The tax forms are very comprehensive. I go through each line of the 1040, following the instructions. Wherever the 1040 references some other form, I find that form, go through every line and follow the relevant instructions there. This approach has even gotten me through obscure edge cases like a company over-contributing to an HSA.

The tax code isn't magic and isn't full of gotchas. The rules may be arbitrary, but they're easy to follow and the IRS won't punish you as long as you're making a reasonable effort and report all of your income. There's an IRS help line you can call. People only really run into trouble when they try to take absurd deductions or claim that whatever tech investment strategy they've invested in doesn't count as income.

If you're scared of filing your own taxes, I really recommend volunteering for a local VITA program for a year.