The Gemara brings a prooftext from the verse in Shemos (12:17) about the requirement to guard the matzos during the process of preparation. 

And you shall guard the matzot (Exodus 12:17). This verse teaches that one may use only matza that has been guarded from becoming leavened for the purpose of matza, i.e., with the intention of fulfilling one’s obligation of matza with it.

״וּשְׁמַרְתֶּם אֶת הַמַּצּוֹת״ — מַצָּה הַמִּשְׁתַּמֶּרֶת לְשֵׁם מַצָּה. יָצְתָה זוֹ שֶׁאֵין מִשְׁתַּמֶּרֶת לְשֵׁם מַצָּה, אֶלָּא לְשׁוּם זֶבַח.

However the Mekhilta on this verse makes a play in words. Do not read it as and you shall watch the matzos, rather read it as you shall watch the mitzvos. One should not delay doing a mitzvah lest it turn into chametz.

(מכילתא שמות יב, יז) "ושמרתם את המצות", אל תקרי "ושמרתם את המַצות", אלא 'ושמרתם את המִצְוות'

People can procrastinate and avoid fulfilling obligations. What happens inside a person that he or she delays doing a mitzvah? 

The most common psychological cause is that the person really does not want to do it at all, but feels guilty declaring (even in his own mind) that he does not want to fulfill this mitzvah, so he delays and avoids, hoping somehow it would go away. For example a man might drag his feet shabbos morning and schlepp out the morning until he, e-v-e-n-t-u-a-l-l-y comes much later to shul. Or a woman would delay candle lighting because she’s rushing at the last minute before shabbos. She might genuinely believe that there is no time to get everything done, however it’s always the same few minutes whether it’s winter sunset of 4pm or summer sunset of 8pm.

Another kind of avoidance is the passive aggressive variety. This is when we harbor an unconscious resentment toward somebody, or some thing that we personify. Someone might consciously feel frustrated that he cannot keep his Daf Yomi but unconsciously still derive a sadistic pleasure for disappointing his father, who used to pester him to study when he didn’t want to. It doesn’t make a difference how old you are or even if your father is in the next world. Emotional life like the spiritual life, exists beyond time. Or, even if your mother is long gone, there might be a guilty thrill in running up to the last minute before you light candles, making your mother anxious and frustrated.

One other kind of procrastination comes from fear of failure. Although it is illogical, some people would rather unconsciously engineer their failure then to try their hardest and risk failing. This is because in the former situation there is a sense of control. Plus, one can always tell oneself that if I really tried I would’ve succeeded. So sleeping late, and coming late, or avoiding hedges your bet. If you manage to still come reasonably on time or succeed in someway you’re a winner anyhow. If at this point you fail, you could always tell yourself that’s just because you came late, traffic, distractions etc.

Sometimes it’s easier to say I am lazy or depressed than to face ugly truths such as we don’t really want to do what we profess to want, or maybe we are angry and even sadistic. 

Folks, the gift and curse of psychology is that we can sometimes know ourselves.