Notes

@_Positive thinking_@
to have positive outlook - мировозрение, перспектива
to have a positive mindset - мышление
to have positive expectations
to see the world through rose-colored lenses
to have a rosy outlook
to look on the bright side of life
to view yourself and your abilities in a positive light
to use affirmations
to take credit for positive events - I was programmed to take credit for this = принимать это как должное
to have a greater capacity for love, joy and warmth
to overcome obstacles
to combat negative thoughts
incurable optimist - неисправимый
unquenchable optimism - неутолимый
to radiate optimism - излучать
a contented person - довольный
to regain control over negativity - вновь обрести

@_Negative thinking_@
to berate oneself inside - ругать
to mire down in doom-and-gloom thinking
detrime'ntal - вредный - have a detrimental effect/impact on the environment
to broadcast negativity
to discourage smb
a mood hoover
an inve'terate pessimist - заядлый
to drain smb of energy

More words
to be solely responsible for - единоличная ответств
a whistle in the dark
blind optimism

to be stuck in a rut - колея
to be on cloud nine - Твой отец наверное на седьмом небе от счастья
+to walk on air
to treat smb accordingly - относиться к кому-л. соответственно
If he is a bad person, we should treat him accordingly.