Making decisions is hard. It requires researching, thinking, and evaluating the pros and cons.
Closing our eyes and copy-pasting our earlier decision or decision someone else already made is so much easier. We can avoid stressing our brains.
Maybe, this is the reason why sometimes an engineer would just do exactly the same thing they did in an earlier project. Name the classes exactly the same way, organize the project the same way, etc.
If we're not changing anything from what we did the last time or we learned someone else did in a similar situation then there are two possibilities:
1. We (or someone else) did a perfect job and there isn't any better way to do it.
2. We are not thinking hard enough.
If we're doing exactly the same thing and it requires exactly the same solution then maybe we're not challenging ourselves by trying something difficult or new.
It is certainly possible but less likely that our previous solution couldn't be improved further even if the situation is similar.
Every time we're copy-pasting something we did or learned earlier, we should ask ourselves, is the same solution warranted or am I being lazy?
On a related note: It amazes me to see how a large group of people always vote for the candidate of the same party no matter who they are. Are people following the crowd? Not thinking for themselves? Copy-pasting earlier decisions? Or is a political party a religious affiliation?
Just like that Re-using code is not the problem. Not thinking about alternatives and repeating the same thing over and over is the problem.