I did a number of things like re-shingle my roof, build a storage shed out back and a carport on the end of my house (garage). However the project that made me the most nervous was installing an exhaust fan in our bathroom. The required running electrical to the opening I made in the ceiling, putting up braces to hold the unit, creating a circular hole in the roof and shingles so that the vent wouldn't leak. That was thirty years ago and as far as I know it still doesn't leak, it still works and the house hasn't burnt down. Also built a new deck on the back and had to replace the house sill that had been damaged by rain and carpenter ants. Then I bought and installed an above ground pool and extended the deck out to partially wrap around it. All without the benefit of ever having done it before or google to tell me how.
No wonder I'm tired now.