Only in the sense that if you like it you do more work and so get a better grade
you might just fail the exam
thats wt i think.
Course it will. If someone thinks they are going to do badly in a subject no matter what they do they don't try. If they think they can improve (positive thinking!) they try harder. Also you'll be more likely to "give questions a go" that you might previously have just avoided answering altogether!
If you find a subject fun and interesting you will retain the information better and naturally want to learn more information too so your attitude should make a lot of difference.
I do agree, i try fairly hard in most subjects, very hard in my favourite subjects and then slightly less in my weaker/less interesting subjects. Care to guess in which ones i get the highest marks. I suppose i'm lucky in the sense that my best subjects are my favourite subjects, ie English Literature, History, English Language and Geography whereas i just cannot stand Maths, Science and German.