How to look about transtion is complated?
Let your explorer display the number of blocks confirmed.

As satoshi explains in section 11 of the whitepaper, a bitcoin transaction is never 100% final, but only the probability of it being not-final decreases with every confirmation. What probability of non-finality is good enough? 

People could have any use-case so let people decide for themselves. Most want 6 confirmations safety to buy a car, some want 1 confirmation to buy coffee (and there are people like Roger Ver who want no confirmation!).