Your character plus the vāsanas and samskāras produce KARMA.

Negative thoughts that simply arise and are not coalesced into INTENTION (saṅkalpa) do not produce Karma. We are not responsible for the thoughts that simply arise within the mind, we only have control over reinforcing them through contemplation and intention.

If we keep thinking negative thoughts intentionally about someone and still do not act upon them, then those thoughts do transform the mind (manas) and create saṁskāras which will later produce Karma.

Hopefully, you will do a full circle and come back to a different longitude of personal beliefs and attitude.

The movement from square one becomes a life changer!