Maybe 堕落 .
We do say:
We don't say:
Not to be confused with 脱落 .
Your question is:
Which is the best way to translate "disrespect" in this context?
So you want a Japanese word which expresses the state of disrespecting (i.e. not complying to) your values. That means, we must begin by translating the state of going against your values: "finding excuses and allowing oneself to slack".
If I focus on the "finding excuses" part, I can't think of a word that describes such state, except for the straightforward 言い訳する人 (person who finds excuses). Focusing on "allowing himself to slack" gave me the word 怠け者 (lazy person).
Combining the two, we at least get 言い訳するな、怠け者になるな (No excuses, don't be a slacker) but that's not really creative and doesn't answer you question so let's dig deeper.
What happens when you find excuses and slack off? You lower your value. Use case can be 己の価値を下げるな (don't lower your (my) value).
What happens when you lower your value? You lower yourself down to a point expressed in Japanese as 堕落 (corrupt, degraded, etc.). This may allow the "state of disrespecting oneself until a point one has reached its lower limit" to be translated as 堕落した状態。
I hope the above answered the question partially, if not completely. Next, on to your purpose:
I want to write a short quote to hang up on my wall.
There's always a 4-kanji set for anything (四字熟語). I have gathered some examples that possibly depict the "disrespectful state" you wish to express. Apparently simple search didn't yield translations and synonyms so I have provided simple translations.
- 放恣佚楽 Live one's life doing whatever it wants
- 放蕩三昧 All about sex, drink, enjoying life
- 酔生夢死 Live a dull non-productive life
- 曠日弥久 Wasting years being non-productive
- 腐敗堕落 Spoiled and 堕落
- 飽食終日 Living the entire day in gluttony
They sound like an awesome life, but are basically used in a negative manner, kind of like the seven sins.
Don't ever disrespect yourself.