I've won some good amount with paylay in sports betting in the past but when I start doing it in a regular basis, it seems my overall return is negative.
So my question, do you bet on parlay and why?, and what's the biggest odds you've won so far?

Don't play too much events in one toto bet!
Yes! don't make "a long long list" in only one bet to pump up the prize.
@100 x 2 btc = 200 btc... with 1000 bet 0f 1.10......

The @100 is not only a Cheesy happy number, "i can become rich" but it's a probability number, that your events will be set winning!

Trust me Cheesy bookmaker want that you try to catch this high prize, because more match together implies more difficult (and I think with some numbers it's really impossible win).
A good friend (in the real life) use to bet from 6-10 bet every time like handicap, over 2,5 etc etc....

Him can get really the 90% of single match, but for only 1 every time him loose!
Why?!? Because if you play 6-10 single with strong quotes more @1.70 so far, you can protect your self for the "lucky bad of the last bet". There is also a psychological correlation, to see the prize get up, the vast majority of better, try to place the "surprise" or decide deliberately to point to more bet.