It's not bad, don't worry. You're glad they're left because they treated you badly, and made your experience at gym bad(if I got it right, I'm soo sorry if I didn't), not because you're selfish or anything. ,,Sally" left you for someone who made it bad for everyone, obviously you didn't feel good. Now that it's over, of course you're gonna be glad they left. If you feel glad about them leaving, you just got weight they made on you(and others)off, of course you're gonna be glad. So don't worry, it's only normal, it's all okay and not bad at all❤️