The significant other of the substitute person may not "have enough time" or "be too busy" for a relationship, or they may only be interested for the purpose of sex, money, status, or general need of someone to talk to during times of stress. The substitute person generally won't get the emotional fulfillment from the experience that he/she may crave, and will feel unimportant yet somehow will continue on out of hope.
This can only end in tears for the substitute person.
Swallowing, inhaling, snorting, or injecting yourself with a drug, usually one that is illegal without doctor shopping for a prescription first.
2 Strawz: You been movin bricks, $hasta?
$hasta: UOENO! Up for 24 hours with my lab coat on. Now I need to substanize my body with some alcohol STAT to wind the hell down.
A quote from the low-budget sci-fi/fantasy film The Dungeonmaster, popularized by Adam Savage of Mythbusters, this quote basically means "you may be technically right, but you're not changing my mind." This can come off as stubborn, but it really doesn't matter, since you don't care about the technical "facts".
Person 1: Ugh this character's design is so terrible and pointless.
Person 2: Well actually, did you know that it's design comes from goes on to prove person 1 wrong
Person 1: I reject your reality and substitute my own.
Person 2: -sigh- Okay then, moving on...
Kirito: I reject your reality and substitute my own.
Kayaba: "NICE!! Dungeonmaster!"
Kirito: "What? No! Mythbusters... What the hell is Dungeonmaster?"
Kayaba: "Oh. I was so happy there for a second."
Any replacement for coffee. Energy drinks are commonly used as a coffee substitute. Tea can be a coffee substitute for some people, as well as caffeine tablets.