If someone doesn't like fish or lobster and shrimp, is there a chance they might still like crab?

you have quite the palat. you click canned tuna but not fresh seafood. 

Sure give crab a try but your probably have the same grivence with it

Crab has a mild sweet taste and a lighter texture than shrimp, lobster, or scallops. You might like it!

i only eat prawns and crabs and red salmon , lobster I dont like or shinook salmon and caviar . 

Hard to say really.  What is it about seafood you don't like?  When I was little I hated fish except for canned tuna and crabs.  It turned out that I hated fish because the only fish available to buy was frozen cod which wasn't very nice.  My road to liking fish started with fresh salmon which was so different to white fish it was like a fresh start on the subject.  It made me braver to try more things and I discovered that I do like seafood a lot as long as it's very fresh and there's no white sauce involved.  My sister doesn't like fish at all except for canned tuna.  To her salmon was worse, not better, because it has a strong taste.  Since you do like canned tuna I would recommend trying crab cakes, especially Maryland style with plenty of Old Bay seasoning, and see how it goes.  Don't be disappointment if you don't like them, you will have tried branching out a little and that's a good thing.

If you don't like shrimp or lobster my guess is that you wouldn't like crab legs, claws, or crab cakes, either. Crab is sweeter than the others but it's still shellfish and if you don't like the other two chances are you just won't enjoy crab. Softshell crab is so good, though! 

I'm curious about what forms of shrimp and lobster you have tried (grilled shrimp or shrimp scampi) and was it lobster tail with butter, etc.? Because those are all delicious to me - but overly salty bay shrimp from a can tastes awful. 

PS

If you like canned tuna you should try Wild Planet Albacore (it's the very best tasting canned tuna). 

Maybe, crab is a  little sweeter than these other seafoods. 

Canned is basically salted water and "stuff".  Tuna steak was closer to the real thing, however the way that it was prepared and cooked MAY BE THE REASON YOU ARE OFF about it.  Have someone else cook it and try it again.  Remember it has bones so you got to pick out the meat between the bones. That is normal.  It is something you chew slowly for you may have picked up another bone...as you feel it with your tongue and redirect it to the lips to remove it.

. It is no different than having beef ribs...there are bones you can't eat so you pick out.

Crab is an entirely different flavor. A sweet meat. so the side dishes can not be Turnips, beets, or Brussel Sprouts or some other strong tasting vege.  Peas are O.K. and about the only thing I would choose.

.  The best crab is caught out of the sea and tossed in a pot of boiling water right at the seashore campfire.

. I know it is true for trout.. Catch, clean gut pan or roast them(if you are doing the Survivor thing you need to coat the fish in clay and move the fire over and plop it down on the hot earth and put the fire around it again to cook the clay.  Then give it 30 minutes and pull out the hot clay covered fish.  Now, crack open the clay and the skin is pulled away(I eat the skin so it does not freak me.  We are talking trout without scales so 16-24" and all you have is white meat as the bones even pulled away. Don't need anything but a bit of butter.(I suppose catfish can be cooked the same way) I would ask those cooks in Louisiana on the internet. It would be a boneier fish, same goes for suckers or carp.  Some people eat it. All fish taste different from each other.

I never had lobster.  I don't fear it. Just never driven to have it. I will cook it myself because I will try it.

Maybe if you are lucky you will get to try "Flake"

Which are all pan frying in butter...on top of the stove 20 minutes for a 16" fish. with the lid on so it steam cooks.

The chance would be awfully small. Lobster is the mildest of all in your list including crab.

There are a thousand seafood dishes that you may like.  If you do not know , it is best not to take a chance.

Yes, there's a chance you may like it.