Lots and lots of personal stories in this thread, and while I have hundreds I could share myself, I'll refrain and post some "technical" info for
the original poster..

Over 50 percent of people will use marijuana sometime in their life. While intoxication lasts two to three hours, the active ingredient in
marijuana, delta-9-tetrahydrocannabinol, can accumulate in fatty tissues, including the brain and testes. Adverse effects from marijuana use include
decreased coordination, epithelial damage to the lungs, increased risk of infection, cardiovascular effects and cognitive deficits. Unexplained
behavior changes, altered social relationships and poor performance at school or work can signify a drug problem. Treatment requires a combination of
education, social support, drug monitoring and attention to comorbid medical and psychiatric conditions. (Am Fam Physician
1999;60:2583-93.)


Many people first use marijuana because of curiosity, peer pressure, or both. Use is often continued for the desired effects of euphoria,
relaxation, sexual arousal, heightened sensations and socialization with other users. Easy access, expectation of few or no legal consequences,
attempts at self-medication (for physical and emotional problems) and eventual dependence contribute to chronic use.
www.aafp.org...

Most users are moderate consumers who smoke it
socially to relax. We now know that 10% of our population have
"addictive personalities" and they are neither more nor less
likely to overindulge in cannabis than in anything else. On a
relative scale, marijuana is less habit forming than either sugar
or chocolate but more so than anchovies. Sociologists report a general
pattern of marijuana use that peaks in the early adult years, followed
by a period of levelling off and then a gradual reduction in use
paranoia.lycaeum.org...

Heavy marijuana smokers show less evidence
of lung injury than heavy tobacco smokers, and it may be
cannabinoids that are protecting them from developing a condition
like emphysema.
paranoia.lycaeum.org...


Just as most experts agree that occasional or moderate use of marijuana is innocuous, they also agree that excessive use can be harmful.
Research shows that the two major risks of excessive marijuana use are:
1. respiratory disease due to smoking and
2. accidental injuries due to impairment.
paranoia.lycaeum.org...
(Link references several Myths)


Two new scientific studies have failed to find evidence
of brain damage in monkeys exposed to marijuana, undercutting
claims that marijuana causes brain damage in humans.
paranoia.lycaeum.org...
www.erowid.org...
www.google.com...
I highly suggest reading into the drug extensivly before attempting it (or any other drug for that matter). Read with an open mind and steer clear of
the unbias websites that promote fear. Look for facts, medical implications, and phycological effects.. not scare tactics.