[mytheory]

Since no one mentioned it, I have a good news for you: it's a sweet spot between what a project manager needs and a team member needs, it's called a PERT estimate. When asked to do an estimate, give your optimistic estimate, realistic estimate and pessimistic estimate. This allows for a better idea of the risk and padding needed for this task (you don't need to add a buffer in any of those numbers) and the manager can use that to calculate a weighted average (very simple formula that you can find online). It's in the PMBoK, so if you have a project manager, he/she should know about it.