Okayy, First of all sweetie, your a idiot if you are trying to get high of of Methadone.
Second of all,
its used to treat other opiod addictions because of it's long lasting effect, a person should only need to take a dose every 15 - 20 hours rather then for example smoke/inject/sniff a point of heroin as often as possible or as soon as the nods wear off, methadone is more stable, you do not get a big rush from it, that is why its used.
However, if you have no tolerance and you took say.. 30mg of methadone you would certainly get high, probably vomit and feel most of the effects that people are after when taking these drugs, if you have a higher tolerance you may need up to 60+ Mg's but BE careful, fine line between nodding off and death..
Because it has a acid or material in it that your body can't use and it goes to your lungs because it can not use that junk. Then your brain starts to realize that there is something in your lungs that are not suppose to be there.
Therefore, your brain starts to react by working itself to hard, your brain is not meant to be used as hard as it is being used to get rid of the Methadone, so there, your body freaks out, and you get high.. Its the same cycle as smoking weed, cigarettes, snorting cocaine, whatever your doing, its bad for you and your body knows, and freaks out.
Does that help?