I couldn't help it and I want to share my opinion about the topic. If you've enjoyed your G&T so far then you probably wouldn't want to add other ingredients into it. I like to keep G&T in the form Gin, Tonic and Garnish. What are the things that might cause you a bad experience with G&T? First of all it might have been poorly served. Proper serve would be large highball glass or balloon glass filled with a lots of ice and Ratio 1:3 Gin to Tonic Water which may vary slightly depending on particular gin brand. Preferences of gin brand depends on a personal taste but I agree with Fever-tree tonic water as a best on the market. Garnish is not a matter of either lime or lemon, one of the great garnishes is slice of pink grapefruit which works well with a majority of gins, garnish should not overpower but compliment G&T and lastly good quality gin does not need squeezed lime inside.
These are my personal preferences so maybe somebody is gonna be inspired by that:)