I can understand shinobi. It does happen. I was tattooed by an artist of considerable repute last year, saw his work in magazines, etc. I went with a "trust me" for a sleeve tattoo and am regretting it.
The first alarm bells rang when he inked a perspective line drawing of a phoenix on my forearm. It looked great on paper, but not so wrapped around my arm, it's hard to pick out what's going on and it looks like it has a broken wing and neck. I was in denial for ages and friends told me not to worry as it would all work out in the end. I went through with the full tattoo thinking at the end of the day I will get a great piece of work and I didn't want to micro-manage. But the sleeve isn't great either - far too much solid black, detail on the outside of the foreground pieces has been lost and I've noticed a few errors where lines stop behind foreground pieces, etc. I hold my hands up and think I should have communicated my thoughts and concerns more, but just did not think I would get a bad tattoo.
Same as you, I'm too embarrassed to show it. I've worn a t-shirt twice since I had it and always seemed to see a lot of people with good and fantastic sleeves when I did!
If you're having doubts now, with a work in progress, I'd seriously consider whether you want to go through with it. I wish I stopped after the first session with the linework, but hey ho. I'm looking to remove too if I can scrape the money together so will join you posting on the removal forum!