I made a new 1.8 Creative world with cheats enabled and bonus chest. In Creative mode I can break blocks but as soon as I swap to Survival I can't break anything. I can hit entities, but no blocks or grasses can be broken.

When I click on a grass my hand/tool swings once and doesn't complete the break.
When I click+hold on a block the same.

If I swap back to Creative I can break blocks.

A new world started as Survival is able to break blocks.