Usually several factors go into being focused (not necessarily ranked in order): * Determination. How much do I care about this feature / bug fix? * Long blo

Usually several factors go into being focused (not necessarily ranked in order): * Determination. How much do I care about this feature / bug fix? * Long blocks of quiet. No distractions. This is usually why late at night works really well for me (no interruptions for meals, no emails, etc). * Interesting factor. Doing drudge work is highly unmotivating. Using a new technology or building something I consider cool (say, a compiler) is tons of fun and I can't rip myself away from it.