It depends what you’re vaping. There are ingredients that are now banned in the EU, which you won’t find in TPD tested 10ml bottles. Shortfills are untested generally, although some more responsible manufacturers have stopped using those ingredients completely.
Some people react to PG, others can’t tolerate too much VG (like myself). Flavours... well, you really have to experiment with those to find what works. There are cooling ingredients too, that give an ‘icey’ sensation, some people don’t react well to that. It can be a bit frustrating when you first start, getting excited about a new liquid you’ve bought, and then finding it’s grim
Vampire Vapes are decent. TW make decent liquid too. Stick with it, you will find what works.