My first few chapters on my current series are just down right embarrassing, art-wise and just some key moments where I perhaps had a lapse of judgement. I've gone back and edited a few glaringly obvious mistakes, but if I get into the mindset, I'd be forever redoing bits.
Funnily enough, I'm not too harsh on older fan comics (as bad as they are), the art was somewhat consistent throughout because I didn't deviate too much from the source material I guess.