When the task requires some effort, it's obvious that it's easier to just not do it, even if desirable. The least effort it requires, the harder it is to deny it (e.g. smoking).
Maybe, but I'm not sure that always holds up. Playing video games requires effort, but many people find it difficult to refrain from that. This may be confounded somewhat, since in some cases procrastination might be mistaken for lack of restraint. But I don't think that's always the case.
There must be a distinction between deliberate effort and flow effort? One weird thing I note is that reading highly technical articles online is easier to make myself do than reading technical papers (even if the article is roughly as difficult). It's like the same task but the classification causes me to make different decisions.