I have often read that you shouldn't meditate to try and have a pleasant experience because meditation is about "letting go" and cultivating equanimity etc and not about trying to feel something else. But then what is samatha? It's tranquility ie a calm pleasant experience so therefore if you do that kind of meditation then aren't you trying to have an experience?
Undertaking the practice of Samatha meditation, should be done for the sake of the practice itself - not for seeking out pleasant experiences. The minute one is thinking about achieving and gaining pleasant experiences, one has fallen into the hindrances. As a result of that, one has moved away from the primary object of meditation and thus are not cultivating concentration any longer.
It comes down to ones intentions for doing the practice.
Its a good idea to regularly clarify and affirm ones intentions for practicing - especially with Samatha meditation, that is very important. Its easy to become attached to the pleasant sensations this type of meditation practice can result in.
One should ask oneself why one takes on this practice. A wholesome intention is essential. Wholesome intentions for engaging in Samatha meditation could be:
- Collecting the scattered mind (e.g. to be used later for Vipassana meditation)
- Deepening serenity
- Purification of the mind stream
- Cultivating a high level of concentration (e.g. to be used later for Vipassana meditation)
Meditation based in "letting go" & equanimity leads to calm (samatha).
The Sutta states that when we are morally virtuous, the other spiritual states arise naturally, without even the need for cultivating them volitionally (cetanā’karaṇīya), thus:
(1) For the morally virtuous (sīla,vata), there arises freedom from guilt, appaṭisāra.
(2) For the guilt-free, there arises joy, pamudita.
(3) For the joyful, there arises a zestful mind, pīta,mana.
(4) For the zestful minded, there arises a calm body, passaddha,kāya.
(5) For the calm-bodied, there arises happiness, sukha.
(6) For the happy, there arises concentration, samādhi.
(7) For the concentrated, there arises the vision of true reality, yathā,bhūta,ñāṇa.
(8) For one who sees true reality, there arises revulsion, nibbidā.
(9) For the revulsed, there is letting go [dispassiom], virāga,
(10) For the dispassionare, there is
(10) the knowledge, and vision of freedom. vimutti,ñāṇa.dassana.
This passage, in other words, elaborates on the 3 trainings (ti,sikkhā) into their various progressive stages, centred around meditation, that is, based on moral virtue (sīla) (1-2), we have good mental concentration (samādhi) (3-7), which in turn bring us liberating wisdom (paññā) (8-9)
As you progress in the path you get pleasant feelings. Also this process is without intention. This includes that you should not try to get any of it or progress. You should not try but let it unfold.
The term cetanā’karaṇīya (= cetanā akaraṇiya) refers to our meditative progress beginning with the cultivation of moral virtue, stressing its importance. If we are well grounded in moral virtue, then our meditation will naturally progress. This is because moral virtue is about the cultivation of the body and speech. It is not about wishing, belief, prayer, vows, rituals, or even religion: it is that moral virtue is the basis for mental cultivation and inner peace.
The Sutta commentary says that the phrase cetanā,karaṇīya means “to be done without having thought, considered, mentated” (na cetetvā kappetvā pakappetvā kātabbaṁ, AA 5:1). Proper meditation, in other words, is a thought-free process, in the sense that distractions have to do with thoughts, and our efforts should be to let go of all thoughts in due course. At least, all our thoughts, in a positive sense, should be directed to our meditation object.
In other words, we need to suspend all deliberating, which is, after all, thinking. Letting go of all thinking, our mind begins to settle ever more fully and deeply so that it can directly feel or experience true reality. Initially, we simply give our full attention to a suitable mental object, such the breath. As we watch the breath, it becomes calmer and still, so does our mind.
This means that if we are morally virtuous, our efforts in meditation would work out naturally by way of conditionality (one wholesome state leading to another), without any need for thinking. Indeed, in meditation, any kind of thinking would prevent us from attaining samadhi, although its proper use (ie, by directing the mind) is necessary in the cultivation of wisdom (paññā) and spiritual powers (abhiññā).
Introduction to (Dasaka) Cetanā’karaṇīya Sutta by Piay Tan
The pleasant experience is there to let you know that what you are doing is efficient. In contrast to an unpleasant experience, like mental suffering, which indicates that what you are doing is inefficient. In what respect is it efficient or inefficient? With respect to creating or sustaining life that builds on , and works with, reality, rather than destroying constructs and working against it. Much like a fractal algorithm (youtube video). With the right formula, the pattern becomes more and more detailed and never runs into a dead end. When you don't apply the same working formula over and over, it runs into a dead end and it no longer becomes more and more detailed. The same with life, apply the correct formula and it keeps growing. That is what your senses reflect. That what you define as pleasant while meditating is a sense that indicates that your mental activity is adding to life, instead of the opposite.
That said, just as the other answers already mentioned. If you are seeking out the pleasant experience, you 'forget' the function of experience. Then it is just like taking drugs to feel happy. What would it add to life if you would only feel pleasant and it wouldn't reflect that what you are doing is good or bad with respect to life? That experience wouldn't have more purpose than only make you feel pleasant. With respect to the greater good, it is useless. Real happiness comes from adding to the greater good. I've created a 5 min video that explains what spiritual enlightenment is. It might help to understand the purpose of experience.
You certainly should pay attention and enjoy pleasant experiences, and investigate at the same time, if you don't already know, what it is that you are doing, so you can cultivate that doing.
So in that respect it is perfectly valid to seek out this pleasant experience. As long it is not your end goal. Your end goal should include adding to the greater good and not being isolated to your mind only, in my opinion.
This is all based on my own experience, though I might stated somethings as fact, of course this is all just my perspective.