Defending the Eucharist as apex

[CallingAllCars]

I am a practicing Catholic that tries to live a fulsome life with a strong faith. I find that Catholicism always has an answer to any [relevant] question. After exhausting various literature (off- and online), I need your help with the following.
Most literature on the Eucharist mentions this sacrament as the apex of Catholicism - the “source and summit”- and it also explains transubstantiation, confessing prior to Communion, etc. etc.; however, how do we explain that a person who Communes could/can sin the moment she or he leaves the church building? If the power and significance of the Eucharist is such, why could one sin shortly after Holy Communion?

 

[otjm]

If the power and significance of the Eucharist is such, why could one sin shortly after Holy Communion?

The power of the Eucharist is for us to accept and use. It is not a power that removes our free will and choices.

If one sins after receiving the Eucharist, one does so because one chooses to do so. It is not a “mistake”, or something we “did not mean to do”.

We meant to do it and we did it. And that is something many people have trouble with, as they do not want to be self-honest. And that - our inability to come to terms with ourselves - is one of the strong reasons why we need the sacrament of reconciliation - as it challenges that weakness in ourselves.