It's probably rare for most reasonably competent people to find themselves defending their actual work and consequent results—which is totally valid if you're really good; morally righteous if you suck. Instead, those close to us often find a need to put us on the defensive by asking us to rather meticulously account for ancillary things, such as time management over the day's time, rote tasks, etc.
"What did you do today?"
It's usually innocent but, depending upon your personal situation, can be loaded. For instance: if you're employed full-time, that could simply mean an inquisitive and innocent "tell me about your day." But if you're not, you may be in some sort of business startup, working various entrepreneurial endeavors where payoff is not even obvious to yourself—much less to those close to you...and yet, you persist for the love, passion, allure, and prospect of it, which only you truly halfway—but almost never fully—understand.
Or, you may be a total lazy derelict...in which case, the following advice does not apply and won't work: except to make you look even more depraved.
...Via self experimentation, I have determined the optimal, most efficient means of answering the question when asked...when I'm too busy free-range contemplating, concrete thinking, or even actually working on something.
With an "oh, well," somber, resigned expression you look up from what you're doing:
"Oh, I jerked off to gay porn on the Internet all day."
...Upon utterance, you immediately look back down at what you were doing and resume it in earnest.
Trust me: it works and has legs.
...Beatrice laughs, now.