[pessimizer]

All good pinball players tilt. Owners can make the machine "loose" or "tight" (at least that what we used to call it.) A loose machine allows a lot of tilting, and a tight one only allows slight nudges.

If the ball is coming straight down the middle, there's no choice but to tilt. A really good player will be able to tilt the tightest machine enough to get that ball to a flipper. Also, a really good player is better at judging "straight down the middle" and choosing not to tilt at all. Anybody who is reasonable at pinball can play for an infinite amount of time on a very loose machine.

It's not actually a factor that can be removed from pinball. You can't have machines tilting when people just lean against them, or when a player pushes a flipper button energetically. The owner has to pick some threshold. They're irredeemably physical games.

[nonfamous]

This is all correct. To add some additional colour, the “slap save” is a form of tilting a beginner player can learn easily. If the ball is coming almost down the middle (but not exactly so), slap the flipper button of the closest flipper when the ball gets close. Slap it quickly with your flat hand. Slap it HARD.

The sharp impulse won’t trigger the tilt mechanism, but it may displace the playfield just enough for the flipper to touch the ball when it otherwise wouldn’t. If all goes well the ball will deflect to the other (lowered) flipper, bounce off it, and allow you to continue play in front of your amazed friends.