Getting stuck in one approach

This has been coming up a lot lately. All of the examples are pretty boring, so I’ll just pick one. If you just want to point, you can skip to the last paragraph. 

Basically I’ve been doing stuff where I've gotten stuck in one approach to them. And I’ve felt pretty stupid when I’ve realized that I could do them another way. 

So, here comes the boring example: At my job, I was assigned to glue a smaller thing to a bigger. For some reason, the thought entered into my mind, that I had to put the glue on the bigger thing, which meant a lot more work and so on. Long story short, it would have been a lot more work. When I told a co-worker this, I was informed that I could just put the glue on the smaller piece. 

As I said, I’ve been finding myself in many similar situations lately. And I wonder how many more there are in my life, where I waste time and energy because I form a mental picture of how it has to be done and therefore exclude all of the other options.