Lyric discussion by Cappex 

Cover art for This Is the Best lyrics by USS (Ubiquitous Synergy Seeker)

Seems to me like it's telling the point of view of a drug addict.

"On my way up, wish me good luck Mission control I'm crushing like a monster truck I should care, but I don't care I fucking don't care, don't care"

Getting higher than he should, probably a normal occurrence if he doesn't care anymore.

The chorus sounds like he's on a heavy stimulant. Maybe meth?

"On my way down, kill the lights now Gimme Calcium and put me in the lost and found I don't care, throw me anywhere I'm cool man, possibly beyond repair"

The comedown from most heavy drugs would definitely make you not care where you are.

This is the best, this is the best Probably 'cause I can't let go

He's stuck in the addiction. He's probably conflicted about it

This is the best, this is the best Stop me 'cause I can't say no"

He can't say no. the addiction won't let him.

As someone who's gone through heavy alcohol addiction and in a relationship with an ex meth addict, I feel I can slightly connect with this song. Glad I'm out of that lifestyle.

My Interpretation