LOL I went to school for Cosmetology so we seen a LOT of weird things!
Garnier I haven't heard anything about. Pantene was weird. We could tell every person who used Pantene because that silicone sticks to the hair so much that when we washed it, we could smell the Pantene.
Look on the back of your bottles. The name or names you should look for are Dimethicone, Cyclomethicone, and Phenyl Trimethicone, which are common silicone-based ingredients in hair care products. If they have any of these, you should be using a sulfate based clarifying shampoo at LEAST once a week to strip out some of the build up.
Personally I use Malibu Well Water Treatment shampoo and LOVE the results I get with it. It doesn't have Sulfates or Silicone in it at all and it's $13 for a 1 liter jug at the supply house. I live in the middle of BFE and have very hard water and this stuff has kept my hair from getting that orange tinge to it. I also have to use about 1/3 of this compared to what I was having to use of the store brand stuff. Malibu C® Well Water Action® Shampoo | Malibu C Hair, Scalp, Skin Products