That nagging feeling that you didn't make much progress last year.
I mean, it's completely artificial. January's no different than June, but because it's the start of a mostly-arbitrarily-chosen new year, I'm left with this nagging sense of time having passed when, yo, time is passing all the freakin' time. There's no reason why I should feel antsy and disgruntled in January as opposed to June.
But I do.