it can depend on many factors.
My DS has always been ahead since FYOS. However he truly hated being singled out, extended etc and after a couple of years his reports went form having B's and A's to all C's (in Vic C is the standard grade)
Any way after grade 2 and a huge lot of external stuff going on I said to his grade 3 teacher I am happy for him to just go with the flow etc whilst he recovered from all the anxiety etc. so grad 3 and 4 he had the smack bang average report of all c's exactly where he should be yet I knew he was capable of more..
This year he has had a teacher who truly "Got Him" found where his true talent and potential lie and has been encouraging him to branch out and excel in it and at the same time has used it as a carrot.. If his class work was neglected, falling down in standard etc then he would not be able to pursue his true talent and potential. This year he has half his report with B's working at a mid grade 6 level at things.. The talent and ability has always been there it was finding the means to encourage him to get to hit... I am thrilled he has the same teacher again next year so I am truly hoping for great things as he is so wrapped to have her and she has already lined up 1 major privilege and sought after role for him next year which ties into his passion.. My sons passion is ICT (IT computer studies etc) and has actually been showing his teacher how do do a lot of stuff and can convert work and files from Mac to PC and vice versa as well has has prepared most of the slide shows shown at who school assemblies this year and has just had the honor of doing the Grade 6 graduation 1 which was seen by all the families of our graduating students.
At our whole school assemblies the audio and visual effects are run by students on a theatre lighting and sound booth, ha and a friend have been selected to do that for the year next year so he is very excited.
Sometimes it is not laziness as such but finding a reason to try harder especially if it makes you stand out in a crowd.