Chronic abuse of methamphetamine reduces the number of dopamine transporters in the brain, which may explain why these addicts

Long-term methamphetamine abuse has many negative consequences, including addiction. Addiction is a chronic, relapsing disease, characterized by compulsive drug seeking and use and accompanied by functional and molecular changes in the brain. hope this helps

Taking even small amounts of methamphetamine can result in many of the same health effects as those of other stimulants, such as cocaine or amphetamines. These include:

increased wakefulness and physical activitydecreased appetitefaster breathingrapid and/or irregular heartbeatincreased blood pressure and body temperature 

Re-worded: I have chosen to give love, negativity is too hard to deal with.

What it means: It is easier to just be positive and sometimes people put too much energy into spreading negativity.