[MUXU]

gutermann is good.
different fabric, different purpose, different thread types. my tailoring tutor told us that if you cover the thread with bees wax, it makes the thread stronger and smoother and stays closer to the fabric. but this only applies to hand sewing, not industrial. i dont know what they use in the industry.
silk threads are so nice but so expensive.

but seriously, there are so many types of needles and threads out there. there are specific kinds for tailors and dressmakers and quilters and embroiders and possible many others.