Once a year you choose to give up, for a brief period, something you normally enjoy. In and of itself, that's neither good nor bad.
But if you're honest, you who observe Lent will explain and justify your observance with one or more of the following:
a. it gives you that sense of quiet pride and self-satisfaction (aka self-righteousness) when you hint to others what you're giving up, as some have already trumpeted here on TOL,
b. you're just bowing to social pressure from religious others who'd frown on you not playing along, or
c. you think it makes you more holy and acceptable to God.
d. Probably some mix of the three.
Also, that Lent is temporary (once a year, briefly) is hypocritical...if something's a big enough deal to surrender "for God" once annually, how do you justify indulging it the rest of the year? Is God really going to be impressed because you give up bon-bons or R-rated movies for a several weeks? Lent is purely of the flesh -- substantially no different in motive than Muslims gorging themselves at night during their days of their "holy" fasts.
So let's call Lent what it actually is: a man-pleasing, God-impressing, self-centered holiday to indulge the flesh under the guise of denying the flesh. It's plain old hypocritical pride -- just like the Pharisees of old whitening their faces during fasts and blowing trumpets when they toss pennies to the poor, all in order to appear more sincere and to impress the rubes with their devoutness.
That's you when you observe Lent.
There is no motivation you can come up with for Lent, as it is practiced, that will justify it as acceptable to God.