Are most decisions based on intuition? Deep down?

Humans are born with the intrinsic fight-or-flight response; processed actions and intelligence comes from the
accumulation of many years' experience which can be learnt from past history, so I think yes.

Decisions to act are based on what we think will most improve our condition. That involves intellectually analyzing the situation, evaluating our options, and choosing one. But the actual decision to act is emotion-based. That doesn't mean illogical, just that logic alone does not cause us to act. We have to also feel like acting. Usually to rid ourselves or some discomfort or anxiety, or in anticipation that our actions will bring pleasant feelings.

Yes.

No other answer possible, but maybe a personal example:

Rain on the highway, truck before me, starts sliding. Right or left? Brake or go? -- Logic would have said, left and brake, intution said, right and go.

I'm alive.