Bug to be verified: rash thinking process

It has long been discovered that my thinking process is a bit rash and jumping both in study, work and daily life. This issue occurred as early as I was in primary school. I simply viewed it as a personal habitual problem that would not cause too much trouble, but was not aware of the potential side-effects it would inevitably result in.

What side-effects can be resulted by rash thinking process? Basically, failure to calculate accurately; and then, inclination to avoid calculation-related problems; and further more, incapability to face any higher-level problems which are based on simple calculation. It is a bit disappointing for me, as many objectives I was planning to achieve step by step seems to be endangered or blocked, at least judged by my currently rashly-thinking mind.

However, I'm going to take it easy, i.e. I'm not trying to be a mathematician or logician or any calculation-related scientist, but I'll try to fix my logical and calculating mind a little before entering the next level of struggling in life.