On the first occasion I brewed all-grain, I mistook how to sparge and ended up dumping five gallons of hot water on top of my drained grain bed... and ended up needing to add a pound of DME to my brown ale to make it something resembling beer.
In my next brew, I found out my wort chiller had a small leak in the worst way, when it completely watered down a batch.
In the middle I've had stuck sparges, stuck mashes, and yes, I've even had to crack the carboy back open to add yeast.
And yet, I just put my 13th batch of the year yesterday. It's all going to make you a better brewer in the long run... or at least, I just tell myself that!