I guess i can take from each gen, just for something i had experience with it.
Also i could say i pick grass/water starters really.
Gen 1: Squrtle
I don't hate it, but i'm somewhat netrual and always was boring to me in playthrough.
I could just replace other pokemon that i loved a lot.
It got a Mega evo, and it was really nice using it in showdown or such. But it was boring still in my playthrough experience.
I loved to use leed seed and draining moves a lot with bulbasaur. Also charmander was a fun memory i had.
Gen 2: Totodile/Chikirota
Chikirota and todidile i never used in playthrough. I was more of an cyndaquil loyal in gen 2.
Chikirota is often sucked, but i had fun with it tbh in HGSS, same with totodile.
Gen 3: Mudkip
Actually like this thing or all starters in general, but least favourite starter of all starter.
Torchic was a hell of fun to use since i liked a lot with fighting type, and treeko have always been a personal favourite of mine biased.
Mudkip is really cool, but also sometimes i have to say i'm really got sometimes annoyed with the mudkip meme a few years ago.
But yeah, loves all of them but mudkip is my least of all of them.
Gen 4: Turtwig
I just didn't care this pokemon so much.
Tried with this guy, kinda fine but i get often off when the starter isn't fast unless if the pokemon can have the draining moves or such etc.
Also ice attacks just crack this pokemon to death.
Gen 5: Tepig.
Self explaining, got tired of fire/ fighting type.
Also slow as fuck, that made me just drop it.
Short and simple. Not hate it, but it's meh.
Gen 6: Chesnaught
Kinda nice typing, but flying type erk also talomflame rip.
Like the spiky shield, but still meh for my taste.
Don't hate it, but it's meh.
I think the reason i don't dislike most of the fire starters is because of i really love the speed(fits for my playstyle), which many of the grass/water starter is kinda slow for my taste. In general i just think i dislike water starters more than the others. Most of my favourite was either grass or fire.
Bulbasaur, Cyndaquil, Treeko, Chimchar, Snivy, Delphox.
Greninja could be a fitting pokemon for me, but i just got dropped of it. I just don't know.
Oshawott could potentially be close to tepig in past years, but i loved the little guy more really when i used it a second time. Aqua jet was a funny move and megahorn is a move i like nicely. It may be more, but i'll not overwrite it, so done here.