Good for you! How do you know you ran everything correctly? Just because it doesn't leak doesn't mean that it won't be a problem someday.
Why should you pay a plumber? Cause there's more to it than just a little glue and primmer. A lot of plumbers are small businessmen. If they could clear that much an hour everyone would want to be a plumber. Factor in the cost of his vehicle, gas, insurance, workers comp, tools, inventory, licenses, training, taxes, clothing, overhead, bookkeeper, electric, cost of carrying receivables, and if he has a helper, add a whole lot more. He wishes for a small part when the dust settles.
And why do you want to come on here, your first post and bash some of the hardest working trades people in the business? It's OK to be proud of your accomplishments, but not at the expense of some trained professionals who spend much of their days cleaning up the mess of homeowners who have no idea what they are doing.