John,
There are indeed plenty of 'boring' times. There are also plenty of busy times. All depends upon the job. I work as a TPI in shops and in the field. There are times I can't stand it. How do you think I find time to write articles for IT? I use situations at the jobs to provoke me to more study and then write about it.
But there are times when a shop has dozens of employees all working on your project that you can't hardly keep up with all the material id, small parts observation of heat number transfer, fitup, welding, compliance to structural drawings, final sign off, record keeping and daily reports. It will run you ragged.
I also have many discussions with QC personnel about improper inspection practices. Those can be fun.
Have a Great Day, Brent