I've got about 50 hours of tattoo work so far, (just the beginning

).
A lot of really good shops, will take a persons idea and make it into a tattoo that will work. Just because you go in there with a drawing that may look good on paper, it will not always look good as a tattoo. Trust the experts (if in fact you are dealing with a good artist, there are a lot of bad ones out there). Things like lines that are too fine or close together, don't always work for tattoos because as you age the lines get a little wider as your skin loosens up, and if things are too small or close together, eventually it will be a blob of ink.
You also have to remember, the artist is going to want to enjoy doing the tattoo. If its something he hates, its not going to come out the greatest. A lot of shops these days are so busy, and the artists are so good they can choose to only do custom pieces in styles they like. May need to find an artist to fit that particular style more than anything.
I draw myself, and I know what art I like, sometimes those ideas won't always work. Now if they are just being a jerk ,then they aren't the artist for you anyways. There should be a little room to compromise if the design looks good, and will make a nice tattoo.
Here is one of my bigger ones. Its not 100% finished in this picture, but it goes from my ankle to my kneecap. He did an amazing job on this piece in my opinion. Some of you may recognize the book!
http://viewmorepics.myspace.com/inde...ageID=50381175
Had my sleeve done at a very good shop in town.
If anyone wants any recommendations on shops, pm me, I've been in a lot of them here in Calgary, and I can point to some links of places with some good stuff just checked and my sleeve has just been posted on one. Someone mentioned strangeworld tattoo earlier, that is a very good shop, at least the last time I checked.