So, that year, whenever I would have such a thought, I'd tell myself that I forgive my past self. "It's ok!"
And it has been extremely effective! I don't think I procrastinate less (or more) on laundry nowadays, but I can't remember the last time I went to bed feeling terrible about myself. It almost feels absurd to me now to think about, but it's actually been life-changing. And it required no money, no explicit commitment, no lifestyle changes, no time taken out of every day. Just a small but persistent voice objecting to the self-loathing.
Downsides might include being overall more apathetic and possibly less motivated - but that might also be an illusion. I don't know, it's hard to compare to beforehand, and I don't think terrorizing yourself is particularly effective in the first place. But even if I had to choose, I would definitely pick "slightly less productive" over "self-hatred".
People say to love/respect yourself. Not hating yourself is a pretty foundational step in that :)