The idea of practical sacrifice is apparent throughout the bhagavad giitaa (especially throughout chapter 4; see verses 23-24, and 26-33 for relevance to this rant/entry).
In chapter 4, verse 24, the idea of the vedic sacrifice is related to brahman, or Universal Self. As Shukavak N. Dasa points out (in his translation and analysis), this is a metaphysical interpretation of the Vedic sacrifice. Because of this, two important conclusions can be drawn. First, the Vedic sacrifices and rituals, with the essence of this verse in mind, become acts that pertain to brahman, or the Supreme. That is to say, they cease to be inadequate materialistic rituals that fulfil contractual obligations to Gods, but instead become actions that are directed to the Supreme.
Secondly, we see a further extension of this. By keeping this mindset, the nature of the sacrifice (yajn~a) is changed. Consequently, we can change the nature of all actions we take with this same mindset. Every action we perform can be considered a sacrifice, and thus we fulfil the description of proper action in the giitaa; we act out of sacrifice, and so we act without attachment, which means the results of those actions no longer bind us. We then are performing perfect karma yoga, and we can reach liberation from saMsaara.
From this, the giitaa also mentions that if one performs austerities, it cleanses us and counts as further sacrifice. Fasting, controlling one's senses, and even breathing all become sacrifices to the Supreme.
So let's take a look at the class of renunciates, such as yogii's, swaamii's, and saadhu's. As ascetics/monks, they forego many different things for a life of renunciation and penance/sacrifice. But, let's analyze this a little more closely.
Ascetics are supposed to forego possessions, luxuries, and the like. This is all well and good, but when things turn awry for others, we have to re-evaluate the process, right? In the SwaamiinaaraayaNa sect, at least in all instances of common practice that I've seen, there is a rule for ascetics that they are not allowed to view members of the opposite sex. This is very strict, and includes family (sisters, mothers, aunts, etc.). From my experience, they do not allow women (though that may be different by sect) to join the ascetic orders, and so we're left with sexist circumstances. That's not to say they do not respect women, but it's hard to teach gender-equality when you have role-models who follow this practice. Often, improper conclusions can be drawn by lay people.
My problem with this is that they're taking the easy road. It's simple to avoid sexual impulses (at least if you're heterosexual in this example) or the desire to buy things if you never see any women or have no money or means. If you put yourself in a situation where you are not ABLE to give in to desires, then you can in no way give in to them. This isn't really controlling desire, is it? If we don't have the free will to desire and act on those desires, can we really say that we're controlling them? If, however, we do have the ability to act on our desires and we choose not to, then we truly are controlling them, are we not?
There's a practicality, of course, to putting yourself in that kind of a position. Yes, desire is a massive fire that seems impossible to control. So, putting yourself in such a position to control it makes sense. Or does it? Often, you hear about not relying on external means for spiritual contentment, yet isn't your way of life directly affecting it? In my opinion, it makes sense to learn to curb desire when you know you can't act on it, at least for a time. Once you master that, you have to take it to the next level, which is controlling it when you are able to act on it. That's true discipline.
So my charge to yogii's, svaamii's, and saadhu's alike is to put yourself in the real world. Escapism is a topic for another day, but while it's on my mind, I'd like to point out that Sufis are strongly encouraged to have families, work at jobs, and contribute to their communities and societies. What's more interesting is that this isn't considered to hinder them; on the contrary, without those very things, they'd have a much more difficult time reaching their goal.
My charge to everyone is to develop self-discipline. But, don't be pretentious or arrogant, or act self-glorified when you know that the only difference between you and others is that you're forced to not act on your desires. If you were voluntarily sacrificing, then perhaps it would mean something to you, and maybe you wouldn't be so self-righteous. Maybe, just maybe, you'd remember how hard it really is, and maybe you'd harbor some compassion.